I used to say I would NEVER do this. Then years ago I took a trip to WDW solo, since I couldn't find anyone to go with me. I was apprehensive, and worried that I'd be lonely and starved for conversation. However, it turned out to be the best vacation I've ever taken. I loved not asking anyone what they wanted to do next. It was just me, me, me, and it was alright.
Now I love doing Disneyland solo, as well, but I can't do it anymore since my kids are old enough and would kill me if I went without them.