Originally Posted by
Huntsman Spider
Peter's first meeting with Mary Jane Watson, because that to this very day remains one bombshell of a way to introduce a love interest.
The moment in Amazing Fantasy #15 where Peter Parker has his epiphany that great power must come with great responsibility, because that set the stage for everything that followed in Spider-Man.
The moment in Amazing Spider-Man #33 where he, with more strain and effort than he'd ever exerted at that point, lifted a great weight off him in order to get the formula that could save his Aunt May's life.
Gwen Stacy's death, because as horribly cliché as it is now to see a female love interest die tragically and violently to motivate a male hero to seek revenge, the actual death of a love interest was something utterly unexpected in comics at that time.
Peter finding out Harry Osborn had been heavily abusing drugs, because that was the first big strike against the Comics Code Authority for trying to circumvent a story warning about the dangers of drug abuse just because it featured drugs at all.
Spider-Man getting the black suit in Secret Wars #8, because that was the beginning of what would likely be the most popular (or at least most strikingly iconic) villain Spider-Man's ever had.
Spider-Man casting off the symbiote in Web of Spider-Man #1, even at great risk to his own life . . . and shock of all shocks, the symbiote seemingly dying to protect him in spite of his rejection of it. A bittersweet moment that demonstrates the kind of impact Spider-Man can make on someone, even if that someone is an alien symbiote.
Mary Jane admitting to Peter that she's known all along about him being Spider-Man. Usually, the love interest has to be told or shown by the hero that her boyfriend and the hero who keeps saving her are one and the same. In this, the love interest actually figured it out long before the hero was ever ready or willing to tell her and just couldn't contain herself anymore after realizing he was going out yet again to possibly get himself killed going up against the forces of evil.
Mary Jane resolving her family issues, with Peter by her side to provide emotional support, and then finally accepting his proposal, having become a stronger, emotionally healthier person after overcoming an all-too-real challenge for many people in the world --- families that are less than nurturing, and sometimes downright toxic and destructive.
Peter and Mary Jane's wedding --- for being one of the few superhero weddings that wasn't broken up by a super-villain at some point. Also, as a nice way of saying "f*** you, Marvel, we're not forgetting this just because you don't want it to have happened. It happened. Deal."
Cosmic Spider-Man thrashing the Hulk, because that was just too awesome for words.
Spider-Man thrashes Fire-Lord despite Fire-Lord being a vastly more powerful being than him, just out of sheer determination and willpower to delay Fire-Lord from hurting innocent people.
Spider-Man takes on Iron Man once he realizes he's been on the wrong side in Civil War. You'd think Iron Man would have Spider-Man completely outgunned, but Spider-Man manages to turn the tables rather nicely despite the odds against him.