I have done many parks alone.  It is really nice to be able to do what you want when you want, so I enjoy that aspect of it.  However, it isn't my preference.  The social aspect for me enhances an already great experience!  That is one of the many reasons why I joined this site(I'm new here, haha).  In hopes of making some coaster/theme park enthusiast friends.  Most of my "non-enthusiast" friends enjoy parks and coasters, but not to the extent that I do.  Not to mention most of them are too busy or broke to be bothered going to parks.  And of the ones that I do go to parks with, excluding a few, most of them are ready to go home after a few hours.....  While I like to stay from open to close 99% of the time.  So in the absence of any coaster/park enthusiast friends, I have ended up going to a lot of parks by myself haha.  I promise, I am super easing going, and easy to get along with lol.  It was just a lack of effort on my part to meet like-minded people.  So having said that, I have usually had a really great time at parks alone and will most likely do it again.  But for me, the social aspect is what makes the experience and memories even better!