Everything had started off as a stupid mistake on his part. A very, very stupid mistake that was motivated by his thirst to know more.
Of course, he had to go and break-in into a locked room in OSCORP, and inevitably find chemically engineered spiders- which leads him getting bitten by one of those said spiders and somehow gain superpowers.
Of course he had to look at his father's things and go search for his parent's past and death- which leads Peter to find Doctor Connors, his father's old colleague. The same colleague whom he gave his father's hidden formula, which, of course, turns him into a psychotic mutant lizard-man who was bent on world domination when he tests the serum on himself.
The old saying "curiosity killed the cat" should have served as a warning to him. He should have listened to the quiet voice in his head that said that this entire thing was a stupid idea, and that he should not go looking for trouble.
The added addition of "satisfaction brought him back" is nice and all- up until the point when shit hits the fan, and he is the one left to pick things up- or in this case, to get kidnapped by a supposedly extinct scientific Nazi group that uses a freakin Greek mythological character as their mascot.
Hindsight is a pretty fantastic thing, especially when you are locked up in a cell and bored to the point of insanity.