“I don’t know why it’s so hard for you to think that I can be happy.” BoJack Horseman was a TV star 20 years ago but fell off the Hollywood map. Suddenly his new movie is a hit, and he’s in line for an Oscar nom — so why the long face? Renewed fame has its trappings, and it’s sticking to our hero like, well, glue. Here’s a trailer for Season 3 of Netflix’s animated comedy starring Will Arnett as the sweater-clad title equine.