I like riding alone, gives me a chance to check out riding spots or ride stuff no one else wants to ride, though I normally ride on my own when I only have a couple hrs to spare on a weekend and don't want to drag people out or want to get a cheeky 45mins at the skatepark before work.
Oh remember to take your phone out, once turned my ankle really badly and had a nice 2 mile walk home. Not to much fun....