This applies in business but also in your personal life.
You are going to live a long life. This is hard to comprehend when you are younger. But everything you put your body through is going to add up over time and multiply when you are older. I have seen a lot of people not treat their body well in the early years (e.g., alcohol, or performance enhancing supplements ) and regret it in their later years. Realize you will live a long life and treat your body and brain accordingly.
When it comes to business, you want to play the long game. Keep the end in mind. Forget about the short-term slights or revenge that you really want to take, and play a few moves out in your head. How is this going to play out? What will happen next? And after that? And is that what you want/intend. Make rational, long-term moves. Don’t do the easy, convenient, or feel-good thing today if it’s going to hurt you in the long term.