Frankiel,
I am sure Jundo or Taigu will comment on this response with more insight, and Zen related reflections. They are the men you need for these topics, but I will take a stab
One thing that helped me was the teachings of the Buddha on karma. I learned about them in a Tibetan sense but also have read writings by TNH on them that lined up, and these basics are found in many sutras (which of course are not Shakyamuni's direct words.) Disclaimer aside, the point is that the things that happen in your life are the result of karmic seeds ripening. The situations gain steam when you react in ways that encourage the growth of that seed. You can also choose to mindfully uproot that seed- TNH calls it mind gardening.
For instance, in the case of your friend being hypercritical of you but not receptive to criticism himself, some Buddhists would say that is because you have been hypercritical and not receptive. The situation is in your life because the seed you planted by the action ripened into a scene. So how do you change that? It's all about your reaction to the situation. Were you annoyed, angry? You say that yelling matches occur- that is continuing the undesirable karma, encouraging the growth of a seed that could be uprooted. So how to uproot it? React with how you want the situation to play out in the future!
Those are just perspectives that helped me out, and I noticed a very pronounced change in my life. For instance, I used to have people (co workers specifically) yell at me, like flat out rage fits, quite frequently. I didn't respond well. I began consciously responding how I felt I should, to uproot the seed, and maybe it's a coincidence (maybe not) but my last few jobs have had only awesome co-workers and no yelling! I actually started a journal about the mind-gardening I've been pursuing and the changes I've been marking, and it's really astonishing me.
You can look at it as karma and the Buddha's teachings, or even just psychologically/from a neuroscience perspective. Our brain creates patterns, on a neuron level it has to do with actual routes between neurons being carved (maybe read Buddha's Brain if it interests you) and end of the story is we react to things in accordance with the patterns set, with what neurons we get used to firing. When we are consciously reacting we can rewire our brains, quite literally, changing the patterns and making new carvings. Our neurons begin firing differently, and we create patterns for more desirable reactions, and other people feed off of our reactions and outcomes can change just from that I believe.
All these words are just things I learned that seemed to help me- I don't mean to come off preachy, this is just a subject I spend mass amounts of time thinking about!!! I can get quite nerdy when I go off on a curiosity tangent.
It takes work to change situations, from a science or spiritual aspect, but that is the opportunity to practice!
Gassho,
Dani