After discovering recently that a friend of mine has a 'collection' of watches, it made me think of what I may collect and didn't even realize it?

Would you believe I started collecting Hard Rock Cafe' t-shirts years ago and still add to my collection to this day? I guess friends and relatives would bring me one as a souvenir from vacations and trips when I was younger and I kept the tradition going. I have everything from Australia to Chicago, Hollywood, the Bahamas, Memphis and more recently a friend brought me one from Baltimore of all places. I need a separate closet for all my Hard Rock shirts. What's your 'thing?'