The first time I read it, I disliked it. I read it again twelve years later and I hated it. Ignatius is an unpleasant person and I don’t enjoy reading about his misadventures. This is probably because I’m a philistine.
That is part of the genius of the author though, they were able to create such a reviled character that has stuck with you.
I have read 100's of fiction books and would be hard pressed to recall even 10% of their respective protagonists. I read Dunces once, maybe 15 years ago, and can recall the disgust at that character immediately.