If there is one skill to learn forever, it is the skill to say “no”.

No to the colleague who makes fun of our values.
No to the activities that you don’t want to sign up for.
No to the client that anyway doesn’t respect your material.

However, the people that say the most “no’s” are the people that say a lot of “yes” to the right things. And if we have not mastered the art of saying no to others, we are ultimately saying “no” to ourselves. Is that the life you want to live?