I don't get angry either, and it's a point of contention with my wife (who does). What she might see as "the landlord screwing us over," I'd see as "an unfortunate situation he should have fixed when we told him about it." She responds with rage, and I simply don't.
It occurs to me, anger might be useful in communicating to others that they have wronged you. Measured communication is more easily forgotten, so anger might be more useful in changing behavior.
Of course, it can also alienate and exacerbate already stressful situations...