Drupal Tip #7: User 1
Drupal version: all
Using user 1 as the admin user of a site during development seems convenient, but I've found myself overlooking and forgetting tiny things. Eventually, going back to a live site to set permissions, or change input formats, etc overrules the amount of time spent setting up a decent administrator role.
User 1 has permission to do absolutely anything on the site - so testing can have inaccurate results.
Some internet bad-guys can do some nasty things to the website, or even webserver, should they get their grubby paws on the identity of user 1, which is why I am a bit of a full-HTML-nazi. Also why I don't trust WYSIWYG editors as far as I can throw them. Best make sure there's no chance the user 1 username doesn't have a chance to be published anywhere, by forgetting a posted by, or allowing access to profiles for anonymous users.
Use your power for good and not for evil!