I love a lot of things about it - the variety of tobaccos, the fun of waiting for deliveries in the mail, packing new stuff in to jars....
I think the thing I love the most about it though, if I really think about it, is that it's mine. I smoke with my brother maybe once a month or so, but for the most part, I'm a solo pipe smoker in a sea of non-pipe smokers.
Throughout my whole day, the chances aren't much great than 0 that I will run in to someone else smoking a pipe. Most people that see me smoking a pipe don't even know someone who smokes a pipe. It's MY thing - something that I do that (statistically speaking) no one else does. It's something I'm expert at that no one else I encounter functionally knows anything at all about.
It's like a great secret that I carry around with me and that I can be proud of - a wealth of knowledge on a fascinating subject that no one else in my world knows anything about.
It's mine and that's why I love it.