The person who is not strong enough gives up at the halfway point - but you are limiting yourself before even starting.

Only the wisest and stupidest of men never change.

Table your mistakes, learn from them, then move on.

It is not possible for one to teach others who cannot teach his own family.

When a person should be spoken with, and you don't speak with them, you lose them. When a person shouldn't be spoken with and you speak to them, you waste your breath. The wise do not lose people, nor do they waste their breath.

Learn as if you were not reaching your goal and as though you were scared of missing it

When frying small fish, disturb them little.