Ichigo frequently leaves his physical body lying around when he goes to fight Hollows in the first arc. When he does this in the first movie, some well-meaning person saw the lifeless body on the ground and called an ambulance. When he comes back he finds his body surrounded by paramedics and rubberneckers, and when he gets back into his body he has to overpower the paramedics to get away, because he was legally dead for god-knows-how-long and they really wanted to take him to the hospital to make sure he's okay.
Under normal circumstances, telling enemies about your powers is pointless if they're overwhelmingly powerful and the enemy they explained it to failed to beat them. Several people, however, such as Ichibei, Nianzol, Rose, and even Aizen find out the hard way that explaining them will get you defeated or even killed when your opponent inevitably figures out your weakness as a result.
A lot of conflicts come from the fact that Soul Society work under some very archaic traditions and rules which many of the higher up follow to the letter. This has lead to many of the more unsavory characters such as Aizen to recognize this and exploit it for their own benefits or created enemies that didn't need to be (such as the Quincys or, as the filler show, rouge Soul Reapers or creations such as Bounts who just wanted somewhere to belong.) which in turn has nearly doomed the realm on many an occasion. Tradition is fine, but eventually there are some that don't need to be continued or need to be reconsidered since even then thought processes will change with the time, especially if it blinds you to the dangers around.
Substitute Shinigami Arc
In the first chapter, Ichigo spots Rukia coming into his house through his bedroom window. Even though she's not there to hurt him (thinking he can't see her since she's a spirit), he quickly attacks her, thinking she's a thief.
When trying to deal with a Hollow attacking his family, Ichigo tries to help... and ends up getting smacked aside for his trouble. Although experienced in dealing with ghosts and street fights, he's never had to actually fight a spirit before and doesn't really have any special power. What's worse, his jumping-in causes Rukia to get injured as well.
After the events of the first chapter, after accidentally taking Rukia's power into himself, you think Ichigo will take up the call to arms when Rukia explains he has to act in her stead until her powers come back. Nope! Ichigo was just concerned for the welfare of his family and was in a desperate situation at the time that would've resulted in all of them getting killed if hadn't done anything. But once the danger passed, that was it as far as he was concerned, he just wanted to go back to his usual life and fighting monsters wasn't something that was appealing to him. He only relents after seeing an child spirit being hunted by a Hollow since even Ichigo isn't that callous to allow harm to come to innocents.
When fighting against Hollow Sora (the corrupted spirit of Orihime's brother) Ichigo has a clean shot at his neck. But ultimately hesitates and get smacked aside for his trouble. This was someone he somewhat knew in life note Ichigo saw Sora die, and was acquainted with Orihime and, still being new to being a Soul Reaper, he's not prepared to deal with such encounters, especially when he's never killed someone before (the Hollow from the first chapter doesn't count because Ichigo thought it was just a monster; it was in the Hollow Sora battle that he learned that Hollows were once human souls).
After a televised event with Don Kanonji in which Ichigo, Rukia and some of his friends are caught on camera (the former two trying to stop a Hollow), the gym teacher has them brought to the principal for apparently delinquent conduct. Subverted when the principal doesn't really care. Paraphrased: "They didn't do anything lewd, so it wasn't a big deal."
When Rukia runs away and is attacked by Byakuya and Renji, who wish to bring her back to Soul Society, Ichigo comes to the rescue and is quickly beaten down. Even with his Heroic Second Wind against Renji, Byakuya takes him out with ease. After all, the two are experienced Soul Reapers with years of combat under them while Ichigo has just barely even started in his stint as one and hardly has a full grasp of his powers.
While Ichigo is training with Kisuke, Yoruichi (in cat form at the time) trains Chad and Orihime in their newfound powers. They do so in an abandoned building but an explosion they cause forces the two to quickly leave the area since it likely will attract attention and they certainly wouldn't have an explaination for it if caught.
Soul Society Arc
After Ichigo defeats one of the gate guards, said guard is about to let him through... only for the group to instantly run into a Captain, Gin Ichimaru, who quickly knocks them back and punishes said guard. After all, the guard isn't supposed to let threats into the place he's guarding, personal code of honor be damned.
Most of the Soul Society residents are comprised of mixed families since not all souls that depart from the living world are reunited with their loved ones in such a big place, especially when many of the members die at different times. Considering that some family relationships can be utterly toxic and abusive (for example, the Inoue family before Sora ran away with Orihime), this isn't necessarily a bad thing.
After Aizen is believed to have been killed, his lieutenant Momo instantly suspects Gin since he was acting shady around him previously, in addition to his nonchalant demeanor when the body was found, to which she attacks him on sight. Gin's lieutenant Kira defends him and the fight ends up broken up by Captain Hitsugaya who has both of them detained for attacking each other. Unruly conduct is not allowed in military organizations, and you can't attack someone without proof.
Renji defies orders to go confront Ichigo alone. He ends up losing and, while treated for his wounds, is locked up for insubordination. Again, the Gotei 13 are essentially a military and going against orders, especially for self-interest, is a serious offense. He actually would've been executed for his actions but is only spared because the situation is too severe to just kill off someone as strong as him.
People have often tapped into newfound plateaus of power, but then found that they lacked the ability to control it or use it safely. This is especially true with abilities that drastically increase physical performance, like Ichigo's Bankai, Tensa Zangetsu. The most consistent result is that even enormous leaps of power aren't reliable without lots and lots of training and practice in dealing with them. When Ichigo and Renji both end up facing Byakuya, a person who's long-since mastered Bankai and has more experience with it, Renji's is overwhelmed and broken and while Ichigo's Super Speed initially gives him an advantage, it puts a strain on him which he doesn't even notice until Byakuya points out he's slowing down tremendously. Ichigo would've nearly been killed if his Inner Hollow hadn't intervened.
In Rukia's flashback, we see that Kaien, a former subordinate of the squad Rukia was in, had tried to fight and kill a Hollow who had possessed and taken over the body of his wife. Rukia wanted to jump in and help but their captain, Ukitake, claims This Is Something He's Got to Do Himself. This doesn't give Kaien any sort of edge, though; the Hollow proves too powerful to kill right away, and ultimately ends up taking over Kaien's body forcing Rukia to Mercy Kill him.
Aizen fakes an order from the ruling council for Rukia's execution to be sped up, banking on the fact the Gotei 13 are quick to follow orders and won't question it... except a few do since he did so without any form of reason or context for said order. Not all soldiers are similar and can see if something's off if you don't give proper protocol.
Years of devotion only to be shattered when said person abandons you will of course build up resentment as Yoruichi finds out when she confronts her former bodyguard, Sui Feng whom she left behind in the past without a word of explaination.
When Aizen reveals his true colors and master plan, Ichigo and Renji try to stop him to protect Rukia. But the former had just came off a fight with Byakuya and is still heavily injured (heck Aizen even lampshades his spine was damaged, not exactly something a Heroic Second Wind will fix) and Renji is likewise recovering after Byakuya beat him in their fight earlier. So when they try to attack together, Aizen doesn't have to do much to defeat them. This was likewise the case with Komamura who tried to jump Aizen with a sneak attack, but due to his fight with Kenpachi earlier, is not strong enough to do any good though Aizen at least has to put some effort in taking out his Bankai.
Arrancar Invasion Arc
The Soul Reapers who are stationed in the living world have a limiter put on them so as not to cause much damage to the town. This becomes a problem when facing a few invading low-level Arrancar who go all out against them and the most they can do is defend themselves until the order is given to release their limiters to be able to fight effectively.
Hueco Mundo Arc
Ichigo tries to save his power as much as possible so that if he fights any of the Espada he can be at full power. While a smart move, he ends up running into Dordoni, a former Espada himself, who quickly proves too much for him to handle with just his Shikai alone. Despite this, Ichigo still refuses to go all out to win. As a result, Dordoni begins attacking Nel to goad Ichigo into using his full power, while pointing out that Ichigo saving his power might be a smart move on paper, it only works if he is fighting an enemy that actually is weak enough to fall for it, something unlikely when you are Storming the Castle.
Ichigo and Grimmjow have their epic showdown, Ichigo wins, and gets Orihime back. All's well, except he forgot he's still in enemy territory and is quickly jumped by Nnoitra, who waited for the battle to be over to make his move as Ichigo would be too worn-out and injured to put up a fight.
Ichigo thinks he can take on Ulquiorra upon finding out he's only #4 within the Espada ranks, reasoning that their strength is based on a number system. Ulquiorra disproves this notion by going to his Resurecccion and practically curb-stomping him. Rankings don't mean much of anything in a proper battle, only what skills your opponents have.
Ikkaku is stationed at a pillar meant to keep the living world and fake town the Gotei 13 created for the war separate while the fight is going on. However, due to not wanting the other squads to know he has a Bankai (out of fear of being bumped a rank and being assigned to a different squad — he likes working under Captain Kenpachi specifically), he doesn't give it his all against the Arrancar that attacks the pillar and ends up defeated. His friend and former squad-mate Iba, who'd left the eleventh division to become a lieutenant in the seventh, gives him a verbal lashing for letting his pride get in the way of his duty.
Sui Feng reveals her Bankai to be a ballistic missile. While it is a very powerful ability, she nonetheless hates it because she's a ninja, whose expertise lie in stealth and striking fast. A big, bulky and loud missile isn't exactly suited for such a profession and she only uses it when necessary.
When Tosen regains his sight through his newfound Hollow powers, he's so wrapped up in being able to see that he doesn't notice Shuhei sneaking up on him until he lands the killing blow. Shuhei even lampshades the irony of how the old Tosen would've easily been able to counter such a move due to a lifetime of using his super senses to compensate for his blindness. Sensory overload is a real-life condition.
When the Visored join in the war, none of them are happy to be fighting with the Soul Reapers as they were unjustly set to be executed in the past by said group for the Hollowfication condition unwillingly put on them by Aizen and have been living in exile. Strictly telling them they're just doing it because they hate Aizen more. At the end of the arc after Aizen's defeated, they're pardoned and allowed to rejoined the Gotei 13 when given the choice; a few declined and stay in the living world because they're still quite bitter at the system they once trusted and see no obligation to rejoin an organization that readily turned on them on false charges.
Lost Agent Arc
Thousand Year Blood War Arc
When the Vandenreich invade the Soul Society the first time and depart, they claim they'll be back in a certain number of days to finish them off. The Soul Reapers think that'll give them time to prepare against them... only for the Vandenreich to attack earlier then they claimed. They're villains, since when do they need to be honest? It's likewise a pragmatic move as well, to catch them unaware so they can hardly counter back.
Movies and Filler Arcs
In a filler episode, Ikakku is asked to train a kendo team so that they can defeat some jerkasses. As per shonen tradition, he employs Training from Hell... on a bunch of normal students who are definitely notMade of Iron, with no means of healing. By the time of the match, all of them are so injured that only one of them can compete.