If it's a few weeks ago, I would view doing commission as boring. But now I have a better perspective on it. I am sure I have grown a bit as an artist.
When someone commission an artist, they show great appreciation for the artist's talent. It's not money they're paying, it's admiration. I've got this client who pays before seeing the art. She says she's picky when it comes to choosing an artist, and prepays to show trust. heartheartheart
As I've done some commissions, I'd say that the most difficult part is building emotions, especially when your client wants something of the total opposite of your personality. I once had to do this super cute anime couple, without my trademark insanity. It's *VERY* hard. If you can, refuse. But if you can't, I can only suggest that you try not to have negative thoughts about the character(s) you have to paint. They are just different from you, that's all.
Another suggestion on doing commission is that you know what you're painting. Character description is there for a reason. If needed, talk to the client about the character(s). More often than not, they're just too happy to give you details, which might give you ideas.
That's one lengthy piece of writing. I suppose I should stop now before it becomes a preach.