I'm having trouble picking between History and English as my favorite classes. I liked Psychology and Latin as well, though they weren't my favorites.
The only class I've never liked is Math, because just reading and understanding the material enough to have an idea of what's going on isn't enough. You have to strain yourself over it, and carefully reason over every little detail. There's also no room for opinion or self-expression... there's only one way to do it, and only one way to write it. I also find it annoying because I'm expected to show my work... I can often come up with a correct answer but struggle writing concrete explanation of how I came up with it. Basically, it feels like I have to put a lot more effort into math than into other classes, and get a lot less back out of it than other classes despite that.