"POKER RULE #10: The long run is longer than you think... Playing only the best hands can be frustrating... Anger and irritability can arise. The emotions can be severely tested. This is where Zen comes in"
As Marty Schwartz said "When I was able to separate my ego NEEDS from making money..." We have to be aware of our needs, and manage the emotions. You might think this meditation thing is just a bunch of ancestor-worshipping crap. For my whole life, I have not seen anything else addressing the problem of human experience more directly. You can't be "good" by pushing away "bad". You have to allow enough space for all the emotions and enough wisdom to pierce through the core of their very nature and not to fixate and get involve with the thought's content.
You might ask I don't have any pith instructions for the insight meditation from any teacher and I have never looked at the nature of thought and mind. But even with some simple technique of tranquility meditation, you can dampen the power of unwanted emotion a whole-lot with awareness - if anger arise, instead of jump on the wagon and get involved with the content of the thought, don't judge it and rest in the awareness of the angry thought. The angry thought dissolves and a clone arise again... rest in the awareness again - don't fight the thought or get involved - give it enough space and it will dissolve back into the very thing it was never apart of. While with insight meditation, you would look directly at the thought, spontaneous liberate it at the spot and rest in its nature. In both cases, leave the content of the thought alone. Like one of my teacher said: "Leave them (bad thoughts) alone! It is like a horror movie and it is not you."
Some stuff I wrote about the meditation on this thread, might be contrary to your beliefs or what you studied. They are not my opinions but the insights of the two thousand years of practical experiences but I am sure my understanding and explainations are far from perfect. People in the old days would die for this stuff but nowaday, you can get it from a $15 book and we tend to treated it as $15 worth. Give it a little time and see if it helps. Like Buddha said, if it doesn't work for you, threw it out.