Yeah, its not "hard" per say, but just takes a shit load of practice before you're good at it, like anything else really. Cal 2 can be a bitch (depending on your professor) due to having to memorize trigonometric identities. Cal 3 was fun, I enjoyed that. Im in Differential Equations right now, and its not bad. Whats nice, is after the calc series, the class size drops, at least at my school. Only 17 people in my class, which is much better than those fucking auditorium shit shows. I can actually engage the professor with a legit question during class rather than hastily copying notes.