And more. Males (and females) in season will charge you from across a room, and have no problem fighting it out with other pets you may have. They scratch you with their claws without even meaning to, and it's no fun clipping the claws of an iguana that doesn't want you to touch his feet! They require lots of time- preparing fresh food every week, cleaning and disinfecting the tub, the dishes, etc...
But for me, it is all worth it for those little moments you mentioned- when he is wandering around and decides that my lap or my boyfriend's shoulder is the best place in the room, when he falls asleep inside the laundry basket and looks so adorable, or watching him eat and knowing that he likes my "cooking", and that he's growing into a healthy iguana because of all the work I do.
They are just a lot of fun to watch, too, and there's always something new and cool to learn about them.
I'd say 50% of the behavioral "problems" can be dealt with by changing how you interact. For example, my iguana is in season now and bit me (not seriously) because I wasn't paying attention. But usually, I watch him carefully, and if he seems particularly intersted in something I'm wearing, or licks something more than two times, I know he's going to bite it. So I don't give him the chance. I divert his attention, or put him away from me, or back in his cage. I don't let people touch him when I know he's grumpy, and I don't let people on the street pet him ever.
A lot of it is just creating conditions where there isn't a chance for something bad to happen to you or the iguana or others. You can do this by making sure there's nowhere he can get caught or injured, watching him carefully when he's out of the cage, and having a cage that is secure and fun for him.
Also, because of the bad reputation iguanas have, it makes it easy to forget how fragile they are. They hate being handled roughly, and love a gentle touch and a soft voice. My iguana's favorite thing is to be brushed with a soft-bristled baby hairbrush. He closes his eyes and leans into the brush, moving around to get scratched where he wants. Another little moment that makes it all worthwhile! 
