One of the things I found myself doing was exactly what you suggested - thinking more deeply about the "why" and "so what" of the things I loved. We use "love" a lot as hyperbole, so when it comes to figuring what what I really, truly do love, making myself think past the surface is helpful. When I started to make a list, I came up with a lot of things, but questioning myself further helped me refine what I put on the list. 

One other thing I discovered is that I have to make some of the things I love happen. For example, having a good dinner and conversation with friends. I love doing that, but I have to put forth the effort to do so, because otherwise, on a day-to-day basis, it wouldn't happen. Writing out all the things I love helped me see that I need to make them a priority because they won't happen on their own.