What (or is it which) skill did you learn later in life but you wish you learned it much earlier?

Emotional intelligence skills. Stuff like: - regulating your anger or anxiety and handling fear - learning how to solve/prevent conflicts through effective communication - learning when to say no and set healthy boundaries - patience The list is not exhaustive, but I think you got the idea. Also! Communication skills. But here I am reffering at the best way to use your voice, as an instrument, to make people listen when you speak. Playing with your tone, volume, speed, pitch etc. I think people who have this skill are such good speakers and especially storytellers.