I am not Italian and I have been exposed to Fantozzi only through this movie. I have no idea how the others are or how funny it is when someone doesn't use the proper "congiuntivo". I also cannot understand why a movie that supposedly is one of the finest Italian comedies has only three reviewers. So let's start from there.
Fantozzi is not a nice man. He is just as petty, selfish and insane as the other protagonists. The only thing he is got going for him is that he is the lowest of them. In his tragicomic attempts to upgrade his "level" in the corporate hierarchy, a fake value system that overwhelms everything, including his personal life, he goes further and further down on the scale of human beings. That is why I had a lot of trouble empathizing with the guy (since I am so wonderful, indeed). However that is not the point of the movie and, if I can presume that much, I would say that Fantozzi is not a real character, only a tool in this satire of the northern Italian capitalism of the 70's.
The best American analogy I can think of is Charlie Chaplin's Modern Times, but focused more on the perceived status of each person. Runaway classism where everybody fends for themselves and the owner of the corporation that produces everything and employs everybody is God, Fantozzi's world is funny only through the absurdity of the situation, but mostly tragical because of the reality it satires.
Bottom line: Fantozzi is a piece of Italian culture. Italians laugh at it because they were raised with Fantozzi films. Also some of the language puns and implications are lost on other people. However this film is well done, well acted and has some scenes that are fantastically complex. I can't say that I was terribly amused by it, though, partly because I understood the horrible world it described and that still rears its ugly head in our lives even today and partly because the character is a stupid selfish man with whom I could not really connect. On a more shallow level, though, one can laugh at the absurdity of the situations, brilliantly pushed over the top by the makers.
