Why do superheroes always insist on going head-to-head with the one villain who has the power to defeat them? For instance, when The Melter (yes, there really is a villain called the Melter) shows up in town, Iron Man just has to go out and face him and act all surprised when his armor melts (the clue is in the name, Tony).
If he had any sense he'd just get on the phone to one of his buddies: "Human Torch? Hey, since you're immune to heat and flame, could you take down this Melter guy for me? And in return, you give me a call the next time Human Firehose Man gives you trouble." (no, there really isn't a villain called Human Firehose Man.)
In fact, it seems there is only one force in the Marvel universe that is powerful enough to get a superhero to acknowledge that other heroes exist, and to call on them for help: declining circulation figures.
"Ahh! Look out! It's Declining Circulation Man! His Ray of Repetition has shrunk our readership! Only one thing can restore our audience to it's previous size!"
"No! You can't be thinking..."
"Yes! A crossover story arc!"
"Nooooo! It's too dangerous! It could kill all of us!"