Warning: SPOILERS for Amazing Spider-Man #12
Marvel's Spider-Man shares the exact same flaw as his nemesis the Green Goblin: both are far too selfish to trust anyone else other than themselves. Selfishness is a character flaw one could easily expect from the Green Goblin, a classic supervillain who craves power and glory (and the death of Spider-Man), but it is a rather surprising element coming from Spider-Man. Amazing Spider-Man #12 reveals that both characters are more alike than Marvel fans ever imagined.
In current comics continuity, Spider-Man has committed a mysterious act that resulted in his most rapid downward spiral in the character's history. While the reader remains in the dark as to Peter's actions, everyone else in his life utterly despises him for what he did, and even his own Aunt May is horrified at his decisions. The Fantastic Four shuns him, Mary Jane is in a relationship with another man, and the only recourse Spider-Man has is to work alongside one of his biggest enemies: Norman Osborn, who knows Peter is secretly Spider-Man. In this new status quo, Norman is on the road to recovery and is attempting to be a better person, putting the Goblin persona behind him.
In Amazing Spider-Man #12, written by Jim Zub with art by John Romita Jr., Peter visits Norman in the hospital after the latter's run-in with the Hobgoblin (and not even Peter knows his true identity this time). Peter is alarmed at Osborn's condition, and wonders why he outright lied about when he was meeting Kingsley. Osborn can only offer a meek "I thought I could handle it myself" as an excuse. This describes Spider-Man to a T, down to his inability to call for help until it is far too late.
Spider-Man Is Too Selfish For His Own Good
Unlike many other superheroes, Spider-Man has hardly anyone in his corner who knows his secret identity. Outside of a few superheroes, only Mary Jane knew the truth - and even then, Spider-Man waited years to tell her, even after the two were in a relationship. Many of Spider-Man's problems would immediately be solved if he would simply tell his Aunt May, his friends or romantic interests about his superhero activities. Since he's had no one by his side for so long, Spider-Man automatically thinks he must solve problems alone - leading to him failing repeatedly.
This fatal flaw dates all the way back to Amazing Fantasy #15, in which Peter Parker decided to keep his spider-powers a secret from his Uncle Ben and Aunt May. His Aunt and Uncle would have told him to use his powers for good; without guidance, Spider-Man selfishly allowed a burglar to pass him (who would later kill Uncle Ben). The Green Goblin and Spider-Man are selfish in different ways, but the outcome is the same: they hurt themselves and others through their actions.