Yeah I totally understand what you mean. I am a perfectionist, so I kind of have to do it over and over again until I have achieved what I perceive as being the perfect representation. This tends to take me hours, whilst my sister can just sit there and doodle something really amazing in practically minutes.
I feel you brah, Although, I do have a desk. It is cluttered with my computer and shit, so I can't exactly use it for anything like that. I just use a binder for resting on. But it is still uncomfortable. xD