These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Nanatsu No Taizai
Crazy Awesome: While not nearly as much as the mangaka's previous Kongoh Bancho as of yet. The world is filled with warriors capable of causing the ground to shatter beneath them, even a Mook can easily cut down an entire forest with ease. Ban and Melidolas for example destroy the tower they're in an arm wrestling match.
Foe Yay: Ban and Jericho. In their first meeting he strips her (yes, he wanted the clothes but it was obvious they wouldn't fit him) and, in the second, she stabs him saying "I'll crave my name on your heart" and paints her lips with his blood.
King has a brief moment with Ban in the Capital of the Dead Arc when he stabs Ban with Chastiefol while he was leaning on the spear with a flirtatious demaneour.
Ho Yay: With Threader, a guy who appears to be a badassStraight Gay, and Gowther, an extremely effeminate looking guy that could easily be mistaken for a girl. The conclusion of their battle in the Liones capital pretty much looks like something that could fit in a romantic comedy.
Ban and Meliodas. They were ecstatic to see each other again and Ban has the same lack of sense of personal space with Meliodas as with Elaine. In chapter 87 he literally said "I love ya, cap'n" and he obviously doesn't want to kill Meliodas despite he is willing to do so for get Elaine back.
Internet Backdraft: Chapter 79 opens with a picture of Meliodas sticking his hand under the princess's skirt. English-speaking fans did not like that.
Golgius stabbing a man he forced to poison Meliodas to save his daughter. Luckily the man survived.
Helbram attaking the village and putting civilians in danger. His justification? "We need to make the Sins the villains for us being the heroes". Prior to that he said that his dead subordinates (who were giving him power) weren't a big deal because We Have Reserves. No wonder why Guila put a Heel-Face Turn at the end of the chapter.
Squick: Some find some of the relationships presented in the manga to be rather squicky. While opinions differ, a common thing that is often brought up among the relationships is how they consist of characters whose appearances make them look vastly different in age.
Some find Meliodas constant fondling of and general Lovable Sex Maniac antics towards Elizabeth to be rather squicky especially considering that he receives little to no reprimand for his actions from her and instead has Elizabeth slowly fall in love with him. Meliodas being Really 700 Years Old but having the body of a kid is sometimes added to the squicked out factor for some.
Some find Ban and Elaine's relationship to be rather squicky as he is a grown man and she has a body of a child. This is rather in disregard to the fact that Elaine is actually a fairy and Really 700 Years Old, making Ban, a human, essentially the younger of the two. Ban looking and acting like what could be interpreted as a lustful pedophile around Elaine in some scenes however doesn't help much.
When the past relationship of King and Diane is revealed in King's backstory, some found it to be rather squicky and looking like Wife Husbandry due to the fact that he's technically older than her, and that she has the appearance and the personality of a very young child. This is a bit of a contrast compared to the case with King's sister Elaine as the fact that King is being also presented as a child due to his fairy form is disregarded. Furthering the contrast abit is that King's present relationship with Diane is found by some to be okay even though it is technically a complete reversal of their past with him being a child due to his agelessness and her being an older looking woman, a thing that also technically happens to be the gender reversal of Elaine and Ban's case.
While her true age hasn't been revealed yet, some find Vivian's obsession with Gilthunder to be squicky especially considering that she's been in love with him since he was a kid, and that she had taken him and Margaret hostage to prevent them from revealing the frameup of the Sins.
When Gowther revealed his true form, many were confused whether Gowther was a man or a woman due to his rather effeminate features. Some are still confused.
When Merlin finally revealed herself in the present, there has been some confusion over what gender she is. Most of it comes from her first full body reveal which despite presenting Merlin with her rather StripperifficMs. Fanservice outfit, her breasts aren't that pronouncedly drawn big. Fortunately Chapter 84 did a better job in, ah, detailing her (complete with some Gainaxing), making her being a woman much more clearer.