Do not know exactly why, but I just love bikes!  A passion which is difficult to explain to some.  I have had a Susuki, Honda, Yamaha and several BMWs.  Love the BMWs and will always have one!  I ride track, endurance (iron butts), sport touring and cycle/camping.  
Why do I own an Ultra, my second Harley?  A couple of reasons. One is that it is common knowledge that I ride and the first question always is, "Do you have a Harley?"
Answer: Yes, and...
I view a Harley a rolling piece of Art!  Visually very appealing.  I am proud to ride it.  Mechanically - that is another issue!  Getting better, but...  Wish my Harley was as comfortable, smooth, trouble free and reliable as my BMWs, but I still love it.
dean