When Peter (After throwing a football which dented one of the goalposts) is asked if he wants to play football, his response is "Too dangerous". On the base of things, it looks like a sarcastic comment, especially since the trailers show this scene right at the end, after various clips of Spider-Man in peril. But Peter's right, football is too dangerous for him to play... Because he has super strength & could easily injure the other players without trying, as evidenced by the newly dented goalpost.
Judging by how nice Flash was being to Peter at the end of the movie, it seems like his humiliation on the basketball court might not have been the pointless vengeance Uncle Ben saw it as. Perhaps getting a taste of his own medicine helped shape the boy for the better.
Considering that he seemed to know how it feels to lose a loved one, how it feels better to lash out at someone, there may be more at play.
At the same time, it did show that Flash was not a sadistic Jerk Jock that most would come to expect.
Why did the cops show up so fast when Pete messed with the car thief? Because they were watching him so he could lead them back to the boss.
For that matter, the fact that the car thief had this complicated electronic thingy instead of say, a coathanger, should have indicated something about whatever resources he had.
Like back in Spider-Man we have a mad scientist using his newfound powers on the people who cut his funding (though this also happened in Fantastic Four). Peter using his brains to win over a scientist who turns into the Big Bad? Spider-Man 2.
The finale has something that can best be described as a "Chekhov's Disarming". During his run to the tower, Peter seals his bullet wound with webbing. Once he reaches the tower, the Lizard crushes his webshooters, meaning he can't use them to seal up Captain Stacy's impalement wounds later on.
Another reason for destroying the webshooters was so that at the critical moment when he goes over the side of the building, it is the bad guy (in an act of redemption) that is his only hope of rescue.
Some viewers complained about Peter's name being on the back of his camera when he tried to take pictures of the Lizard in the sewer (which lead to the Lizard learning his identity), as he shouldn't have done something too dumb. But something I've noticed in some of the comics (at least the Ultimate ones) and one animated TV series is that Spidey gets cocky sometimes. Considering that he was playing games on his phone while waiting for the Lizard to show up, really lax for someone waiting for a dangerous monster, it probably never crossed his mind that something would go wrong.
The bridge scene is pivot for many reasons to be sure. But also consider that Ben was a draftsman of bridges; while a bridge is certainly an easy way to have lots of tension combined with innocent bystanders, it's perhaps one of the symbols that strikes Peter at the moment to turn from vigilante into hero because he's reminded of Ben in that moment.
Some people on WMG wonder why Manhattan has so many cranes. Then it hit me: if Marvel hadn't been pressed for time, OsCorp would've cameoed in The Avengers, meaning they would be in the same continuity. And, more importantly, there's nothing saying they still aren't. New York has so many cranes because they're still making repairs after the Chitauri invasion!
The ending where Peter implies he's going to break his promise to George Stacy and date Gwen. While it was cute in the movie itself, if the movies follow the comic then Gwen will eventually die after being a hostage in a Spider-Man fight. If Peter would've kept his promise, Gwen would likely live.
Watching Peter so recklessly toss Gwen out a window and then stop her fall by webbing her shows how little he knows at the moment about how fragile her body is. This may come back to bite him...
It worked with a small kid, how would he know?
To be fair with the kid, he caught the kid by the chest. Also, the kid was essentially motionless and vertical while Gwen was caught by the ... ahem... waist and both prone and in active freefall. Maaaaajor difference.
Pre-powers, Peter stole an intern's identity and got him thrown out of an amazing opportunity at a large company. The poor guy's life up to that point was probably ruined and even though it's treated as a gag he seems pretty distraught over it. Rendered less relevant by the whole Lizard incident and Connors going to jail probably messing with the whole internship thing anyway (and Oscorp is likely a lot less prestigious a place to work because of it).
On the bridge - there's a brief moment where Peter contemplates continuing his fight with the Lizard after Crane-Dad shouts for someone to help save his son. If Peter had gone after the Lizard instead of helping the kid, he would've stopped the second half of the movie from happening & saved Captain Stacy's life,, since the Lizard formula's starting to wear off & turn Connors back to normal at the time; but the kid would have died in the meantime, and Spider-Man would be branded a menace who left a child to die since he'd rather continue fighting. Plus, since he'd just told Gwen that he's Spider-Man, it'd more than likely destroy their budding relationship & she could easily tell her father who Spider-Man was out of sheer disgust over Peter letting a kid die.