Here's mine: it turns an otherwise enjoyable activity into work. In my case, I'm thinking/writing critically all day for my clients, and the last thing I want to do, after spending all day in front of a computer screen, laying down words into sentences into paragraphs, is do the same while I'm drinking beer. I gave reviewing a shot a couple of years ago, did a little over a dozen, and I think I did an ok job. But it wasn't fun. At all. Like others here, though I participate in other ways, posting photos in WBAYDN and contributing to threads on the Pacific forum.