It does become habit forming! I started riding regularly last summer, but didn't ride much over the winter. I've been back on the bike since late Feb and wonder why I stopped for the winter! I feel so much better (alert, energetic, motivated) when I ride to work and I'm less inclined to stop at McDonald's or Wendy's (saving money and my health.) I don't ride every day, but I feel better when I do, and that's what matters to me, and thus a habit is born.
This AM, I woke up late... slept through my alarm. I was getting ready for work and really considering driving, but I forced myself to ride, even if I got to work later (which I did, in my job I kinda make my own hours, so that's nice.) Within 5 minutes of arriving at work, I was ready to go and had energy and metal awareness all day. Honestly, I feel so much better when I ride, I feel bad when I drive, but there are days when I have errands to run or club meetings at distant locations so I justify it that way.
As you get started, I recommend using the same strategy, ride when you can, when you have time. Don't feel bad about taking the train if necessary. Above all, have fun!