Bad habits are the result of mistaken beliefs, and also contribute to them. For example, I felt I needed to check my email constantly, or leave it on in the background while I am working on my computer.
The mistaken belief in this case was that I needed to respond immediately to whatever I was asked, and that some great opportunity was going to come my way by way email at any moment. In truth, I do get such opportunities, but they do not require immediate action on my part. I could read email twice a day and do just fine.
The habit is self-reinforcing, in that I get anxious when I don't check. So I get to soothe my anxiety by checking, but actually it would be more soothing rarely to check at all during the course of a day.
Taking the bus rather than walking 10 minutes is also a bad habit. It seems to save time, but I have to be out at least three minutes (for fear of missing it) and then ride it for four minutes, so I am really saving only three minutes, and missing a chance to walk and think more. I have waited for the bus for as long as 8 minutes (if I am early and it is late). If it is very cold I could take the bus, though often times it is a pleasant temperature any way.
Checking stats on my blog is a bad habit. I like the fact that they are rising, so that I can get 10,000 hits a month, so there is a little ego boost that comes with that. I don't see why I need to do that every day, though.