One reason anger exists is to alert us to a problem. You may get mad because one of your employees is often late for work, because your spouse keeps leaving the milk out, or because your printer keeps giving you an error message. The anger you feel is one of the mechanisms your brain has to let you know there is a problem.
A way of alleviating that anger is to solve that problem. If you are routinely finding yourself angered by being stuck in traffic, find an alternate route or leave a little earlier or later when there is less traffic. If you are frequently frustrated by a computer program that doesn’t work the way you want it to, find a better program or work with your IT people to make that program work better.
Whatever the solution, the point is that dedicating a little time to solving the problem is better than letting the problem frustrate you day in and day out.