See, I also strongly dislike Mater. Well, I strongly dislike most aspects of Cars in all honesty. But Mater was (mostly) used as the comic relief for cheap laughs. Maybe Olaf's sense of humor was more my type, but from everyone I've talked to about it, they seem to be in love with Olaf. A lot more so than anyone was with Mater.
I enjoyed Mater. Olaf is like your aunt's Chihuahua that doesn't shut up and never tries to top mounting your leg.
Had I not seen Frozen for free on a cruise and been one of those who paid to see it, I would be ed. The movie was a large let down.