Has anyone here ever legally changed their surname? (Please see details)

Not because of marriage or divorce, but for entirely other reasons. Was it difficult? I know how to do it, and on paper there is a certain tedious aspect to it, but these things still all go through a human component, and that can muck things up.
How long did it take you? Did you have any bureaucratic tangles and delays?
Are you glad or do you regret it?