Very nice couplet, although there are dull stretches.
The personal pronoun "I" should be the coat of arms of some individuals.
To be ungrateful is to be unnatural. The head may be thus guilty, not the heart.
In general, indulgence for those we know is rarer than pity for those we know not.
There is nothing so unready as readiness of wit.
There is even the dignity of vice.