when i worked at the Apple Store / Genius Bar in college, we were trained on "assuming positive intent" from customers and peers. at the time, when i was a shithead 20-year-old, i thought this phrase was such bullshit. of course i can tell when someone has malicious intent, why not respond in kind! but now that i'm a bit older, i've realized the real wisdom behind the idea "assume positive intent" is that, when faced with interpersonal conflict, it's better to take the path of least resistance and keep your cool.
for example, if i'm getting kind of annoyed with someone at work and i want to write a snarky email, i find it best to walk away from the keyboard and write my response when i'm feeling less activated.
the result is that i can feel good about how i handle my feelings, i reflect better on other people, and i'm being an actual grown up. ;~)