If I were a more cunning thinker or a more capable writer, I might post more often; after all, I'm here nearly every day. Most of the time, however, I refrain from posting because I just don't feel as though I have anything meaningful to contribute or otherwise expect that someone else will come along (and they usually do) who will make my point better than I could.
I'm not much of a fan of posting frivolously or jokingly myself, either. Once in a while, sure, but I'm not going to pad my post count with it.
Then there's my indecisiveness. I spent a week mulling over this post and, honestly, there's nothing here I couldn't have written days ago.