being in the middle of doing the work is usually less painful than being in the middle of procrastinating.

I've often heard people say things to the effect of work not being so unpleasant once you've actually gotten into the swing of it, but I've never found that to be the case. I generally only find the act of working less painful than procrastinating when I'm right up against a deadline. Otherwise, even a half hour or so into it, it still feels easier to stop than continue. I'm also quite terrible at creating self imposed deadlines.

In order to increase the pain of procrastination, and the reward of working, I find it extremely helpful to have someone else waiting on me to get it done. It's much harder for me to bear disappointing others than failing to meet my own goals.