Accept your life, or do something about it
I have a new rule for myself that I'm trying to (imperfectly) follow. Whenever you feel frustrated about some circumstance you find yourself in - maybe the bus is late, maybe your boss annoyed you, whatever - ask yourself if it's a temporary frustration or if you've felt this before.
Typically I catch the second kind when I'm complaining about something. The rule is, if you've felt it before: Do something, or accept it.
What do I mean by "accept it"? If you find yourself getting frustrated by something a few times, you haven't accepted it. Acceptance is not resignation or giving up, but it is acknowledgement that circumstances will not change without action. Perhaps your corporate job that you hate provides too many material comforts for you to risk leaving it - that's fine, don't quit your job, but accept it.
I've noticed that the default for myself, and what I observe in others, is instead this strange middle-ground I call "the resentment zone": We grit our teeth and shake our heads, or we vent our frustration to our friends and complain. Yet after all that, we neither take any action, nor fully accept the circumstances we find ourselves in. Why? Fear. To do something about it often means taking risks: Confronting people, quitting a job, facing uncertainty, whatever. To accept it is another kind of fear, fear that you can't have what you want. To accept your circumstances is to kill the possibility in your mind that it'll get better somehow. Staying in the resentment zone lets you preserve some belief about who you are or what you could be, yet never testing that belief in the real world.
Your life is not something that happens to you, it's something you choose every day, even when you choose to do nothing. Do not let fear rule your life, or you'll spend forever in the resentment zone.