Why is it people are wasting away their life in search of Bigfoot ?

i mean come if such a thing was living out there in the woods wouldn't there a be a body, nest, waste or a decent photo of this thing..I saw on TV the other day where this guy has been looking for one for 20yrs man what a waste of a life. If somehting 8 feet tall big and hairy was out there then don't we think someone would have proof by now?