Flying fartnockers. It has enough syllables to make you feel better when you say it.
That being said, a bunch of scientists did a study to find out if swearing in response to injury or stress made the person feel better, and apparently concluded that it did relieve some of the stress.
They must have been spying on me last time I had to tink back about 15 rows of lace knitting with mohair yarn. :-/