being positive is a lie

discernment is paramount. if someone treats you shitty you don't treat them well for it. that would be self destructive 

in game-theory tit for tat is the best strategy

if you convince everyone to be bygones be bygones then psychopaths rule the world. might explain an awful lot about modern era. so to be good, you have to learn discernment and exercise it appropriately

just because you don't like some random person on the Internet or your nosey neighbour doesn't mean you don't have good in your heart either. I would say dealing with people who stress you out internally is not positive at all. it's not about faking it. it's about making decisions that feel good to you, on the inside, spiritually-speaking. don't make regrets, say what you mean, and let things lay where they will, with your heart at peace