Do your best in all things even the ones you don't want to do<br />
The only way to grow intellectually is to challenge yourself and work on your weaknesses, avoiding every situation but the ones you're best at will lead you down a narrow and unsatisfying path where you might not ever realize some of the best things about yourself.
"Don't be good at the things you don't want to do."<br />
If I don't want to do something, I'm very likely not going to do it.
do your best
I do my best to be the best at everything I do