Chronic remorse, as all the moralists are agreed, is a most undesirable sentiment. If you have behaved badly, repent, make what amends you can and address yourself to the task of behaving better next time. On no account brood over your wrongdoing. Rolling in the muck is not the best way of getting clean.
It is far easier to write ten passable effective sonnets, good enough to take in the not too inquiring critic, than one effective advertisement that will take in a few thousand of the uncritical buying public.