Don't let small things ruin your day. If someone else's frustration causes them to act out, it's their problem, not yours. Don't take it personally and move on. Save your energy for real problems.
Take 10 deep breaths, close eyes, meditate for 10-20 mins without resisting or promoting thoughts, accept the situation, find solutions, feel relaxed.
Take a shower and you will feel energized. This is a simple and widely accepted technique. It refreshes your body and mind. Just wipe out all the negativity and get a refreshed start.
Change the place to resolve problems caused by location. Leave the place, take a break, and return for a fresh perspective.
What are friends for? This is the time when you need one of them. Just talk out the problem with your friend. Share your problem and you will feel relaxed. Even if they cannot give you a solution, they will give you the courage to find the solution.