I always found the dramatic side of things easier than the comedy, because there's so many ways to do comedy, and it's also subjective. Someone might not laugh at what you do, whereas if you're going to do a dramatic scene, there's usually only one way you can do it.
There is a little bit of snobbery with casting, and unless you're a really successful comedian like Ruth Jones, you don't get to be in the drama side of things.