I used to get the 'twitters', as I like to call them. It's kind of embarrassing when you're around a lot of people, but chances are, they're too high to even realize it. I don't know why I would occasionally get them, and why I don't any more. It was usually after smoking a lot after not doing so for a long while. Probably had something to do with paranoia. For awhile after I got arrested for possession, I was very cautious (which helped in the long run).