... is to sin. Or so says a 17th century sermon delivered by a Reverend Walker. But, per a Carleton College (Ottawa) website (http://http-server.carleton.ca/~tpychyl/prg/research/research_history_term.html) , procrastination was not always viewed so poorly. The Egyptians observed both a good kind of procrastination (not doing what was unnecessary) and a slothful sort of procrastination ("laziness in a task required for sustenance"). Modern uses of procrastinate seem to associate the task eventually and tardily performed with less than adequate performance.
That same Carleton College sponsors a Procrastination Research Group (http://http-server.carleton.ca/~tpychyl/prg/about/about_research_group.html). I wonder how they get anything done.
