One you can finish

The worker must be stronger than his project; loads larger than the bearer must necessarily crush him. Certain careers, moreover, are not so demanding in themselves as they are prolific in begetting a mass of other activities. Enterprises which give rise to new and multifarious activites should be avoided; you must not commit yourself to a task from which there is no free egress. Put your hand to one you can finish or at least hope to finish; leave alone those that expand as you work at them and do not stop where you intended they should.

~ Seneca, On Tranquility