The wound that bleedeth inwardly is most dangerous

This can be taken as straight forward medical advice but like all proverbs has several layers of meaning.

A sensitive individual suffering a slight can brood silently on the perceived insult and fall to plotting revenge. The sad cases of gunmen opening up on fellow students could be an example of this. To allow perceived slights and wrongs to fester and grow poisonous is not good for the balance of the mind.

People need to be able to express their sense of grievance and find a solution. Good, open, honest debate is a useful method of identifying problems and enables corrective action to be taken. The trouble is, most people leave things too late and by then it has become critical. The boil must be lanced. It is useful to remember: A trouble shared is a trouble halved.

The pain of lost love can "bleed inwardly" but what is done is done. It is OK to mope a bit whilst readjusting your thoughts and emotions but that can't go on for ever. Write a sad poem, share the sorrow with friends, they have probably been there, or play a sad song -- then get on with life. There will be better times ahead.

Humor is also a good way of diffusing tension: a timely joke, or helping the over serious to learn to laugh at themselves, is psychologically very healthy. As the say: Laughter is the best medicine.