I love this movie, but the whole 'never got sick' thing never sat right with me. He had to ask his boss and his wife if he had ever been sick. Wouldn't a 42 year old man know if he'd ever been sick - and if he'd never been sick, wouldn't that have stuck out to him? Plus, everyone knows what it feels like to be sick because they experienced it in the past (i.e. sore throat, raw chest, stomach ache, etc) - you wouldn't have these memories if you were never sick. Seems like M. Knight played this with a bit of a heavy hand.
Other than that, I love the movie. Awesome take of Superheros.