The part I didn’t get was the scene where Horton trips in slow-mo and then, for no reason, starts speaking in a Russian accent.

In retrospect, yeah… that part of the movie did sorta stick out like a sore thumb and didn’t really need to be there, but really ignore that one scene and it’s actually a pretty enjoyable film. Out of all the Seuss books to be adapted, here’s what I think:
 
The Grinch: I will fully admit this may be nostalgia talking since I did see the movie when I was 10, but honestly I like this one. Jim Carry hamming it up, the creative sets and costumes certainly evoking that Seuss feeling, and I honestly don’t think that the added backstory explaining why The Grinch hates Christmas so much really hurt anything. Guess it does help that the director for this one was Ron Howard, who has a pretty good track record.
 
Cat in the Hat: Yeah now this one was just bad, I can’t blame Seuss’ widow for forbidding any more live action adaptions after this. It really wasn’t Mike Myers fault though, I did some digging and found that Universal outright forced him to do this movie because of a contract problem regarding a scrapped film, so my theory is he played the role the way he did as a way to say “screw you Universal, you’re not making your money back on this one!”
 
Horton Hears a Who: The best one so far, made by the same people behind Ice Age. Nice cast, nice animation, expands on the original story pretty well, and also made me both laugh and tear up.
 
Lorax: I’d say it was at least decent at best. It’s from the same people who did the Despicable Me movies, so I admit I had high hopes, and I admit in the end it wasn’t as good as I hoped (especially since Despicable Me was such a surprisingly good movie IMO, the sequel’s pretty good too). I don’t think it’s anywhere near as bad as people like The Nostalgia Chick say, but yeah it is a bit weak compared to the Horton movie.