Haste makes waste.

The saying warns that hurrying a task tends to cost more than it saves. Rushed work invites mistakes, and mistakes have to be paid for in spoiled material, wasted effort, extra expense or work that must be done again. It is stated as a general rule about what haste does, and its lesson is that taking enough care at the start is usually cheaper than repairing the results of a rush.

Haste here means careless hurry, not speed as such: a skilled person working quickly and accurately is not its target. The saying also weighs only one side of the choice. It names what rushing can waste but says nothing about what going slowly costs, so it is misapplied where delay is itself the larger loss, as in an emergency or with a chance that will not wait. It can also be stretched into an excuse for avoidable slowness.

A parent, teacher, supervisor or colleague might say it to someone who is cutting corners to finish quickly, such as a student racing through an assignment or a worker skipping a check before a deadline. It works as a warning given before or during the work, while there is still time to slow down and take care. It may sound like nagging when the person has no real choice but to hurry, or when a small error in the task would do little harm.