I can work with roles, but I find that most of the time this concept is even introduced is in slice-of-life and teenage drama roleplays, and, to me, it's very off-putting. I'm not really interested in playing your made-up characters, I'm interested in playing WITH them. If I don't have any input at all, I'll just pass, because I know I won't be as invested in the character. Also, with the aforementioned tendency of what type of roleplay utilizes these, I often feel the background motivation was self-gratification on the GM's part.