Riding the clutch.

Holding the clutch in at stop lights, signs, et cetera. (Big cause!)

Lots of rush hour (bumper to bumper) driving.

Never bleeding/flushing the system. (should be done every 1 maybe 2 years just like the brakes)

2000 SVT #674 13.47 @ 102 - All Motor! It was not broke; Yet I fixed it anyway.