I think giving people the benefit of the doubt can become a habit.  On the other hand, thinking the worst of people can also become a habit, and I sometimes catch myself drifting in that direction.  "Never credit malice with what is better attributed to stupidity," was how I was first taught about giving people the benefit of the doubt.  I'm not sure my father anticipated how much contempt I would grow to have for lack of intelligence.  I've since changed the version written in my heart to "Never credit malice with what is better attributed to carelessness."  Sometimes even that isn't enough.

I have friends who do things that hurt me (don't we all).  Most of the time, they don't know in advance that certain things will be hot buttons for me, and so I can forgive them for not knowing.  Sometimes, the potential for hurting me would become obvious if my friend just gave it two seconds of thought, but they didn't, and I forgive them for carelessness.  Sometimes they just had other priorities, and I can acknowledge that they have the same obligation to look after themselves as I have to look after myself.  But sometimes too many of these add up, and I sever the friendship.

Sometimes I seethe with unfounded, undirected anger, and I just have to tell my loved ones that I'm not fit company for humans right now.  Sometimes I have to tell my kids to ask me later, because I'm aware that I'm too cranky to make a fair decision.

All of these "sometimes" seem to add up to a "lot of time".  I'm blest that each of these is only a tiny part of my experience of people.  Yesterday all four adults in my house were home together, and we were able to collectively sprawl on the couch and marathon movies with pizza, and have giggling and horseplay and teasing and laughter as well.