Although it is billed as a comedy, and there are certainly comic elements to it, there is a more serious component that underlies it and gives it some depth. Jason Segel plays a slacker who, at the age of 30, has few prospects (and living at home at 30 seems to be the modern stereotype of a loser). Jeff clings to the idea that some 'sign' will appear to show him the way. In fact, he is viewed as nothing but a loser by his mother, brother, and just about everyone else. When someone mistakenly calls his number asking for Kevin, Jeff, seeing this as the sign he's been waiting for, begins his search for his role in the universe, brushing aside all ridicule in the process.
I like movies that show how small, apparently insignificant, choices can lead to life changing events. I also like movies in which a character is redeemed by adhering to principles that everyone else thinks are insane. In its own subtle way, the movie questions many of the basic premises that underlie modern society. Yeah, I know, maybe I'm reading too much into this, but, I suppose, that's why we all like certain movies that others don't.
You're not going to get a better guy to play a slacker-loser than Segel. The other actors hold up their roles well. I admit that I expected little of this movie, but I found it engaging right from the opening scene. Give it a chance and I foolishly believe you will not be disappointed