Basically life and all the, at times quite challenging, relations(hips) and situations at work, in personal life and random encounters. Basically 'taking up on the challenge' instead of a hiding/walking away. This sounds a bit spiritual, but I'm convinced life presents to you the right opportunities for you to grow and it's up to you to face and deal with them in the best way possible.
I'm 41 now and my stance boils down to honor/respect yourself and others, admit mistakes, don't take bullshit, but never escalate, while maintaining a lighthearted, 'don't take things too seriously' approach to life. It helps to be able to 'relativize' (not sure if that's the correct English term, but we use it to take a step back and review the situation) and not get emotionally triggered. Triggers are signs that you have stuff to work on. Learn to recognize them.
Practical stuff: meditation, sports (martial arts), open up and talk to friends or a professional therapist if you need serious support.