Sending multiple revisions to editor/referee
(a) No, I don't have similar tendencies. When I submit a paper for publication, I'm so relieved to have finished it (usually much later than I had planned) that I usually ignore it until I get the referee's report.  I usually have plenty of other tasks that need my attention because I had postponed them while finishing the paper. (b) As a referee, I don't mind getting an improved version of the paper provided it comes with clear information about where the changes are. I don't want to check the part of the paper that I've already read (and my notes on that part) against the new version just to find that nothing has changed in that part.