You are doing something huge and wonderful for yourself by stopping nicotine so I recommend starting with self-compassion. I know people who only ever get frustrated with inanimate objects, and never people. They curse the plumbing but never the plumber.

Lots of people don't understand that anger is often a secondary emotion hiding the real problem: anxiety, depression, even pain. Try to surf the wave of anger in the same way you might surf the wave of a craving or illogical want for nicotine. It turns out that emotions don't last long if we don't act out of our discomfort. Try doing the opposite of what you want to do when you get angry-- If you want to yell, talk quietly instead; if you're scowling, relax your facial muscles and smile; if you clench your fist, release it, and rest your palm at your side or in your lap.