Well, practice makes habit, so I don't see why practice can't make different habits...
Although, I do have to plug a couple of Steve's articles...
http://www.stevepavlina.com/articles...ing-desire.htm ,
http://www.stevepavlina.com/blog/200...helming-force/ , and
http://www.stevepavlina.com/blog/200...lf-discipline/ .
If we practice procrastination, then our habit will be procrastination... Some times, it takes extra momentum to overcome our habits, so if we have a burning desire to make the change, we can attack the habit with overwhelming force, and use self discipline to keep ourselves from slipping back into the old habit.