Well, if it didn't look quite so overlong as a title, I'd make it say, "GIVE THE BENEFIT OF THE DOUBT MORE OFTEN THAN NOT." Because I truly do get that there are plenty of situations when giving someone the benefit of the doubt is *not* the best idea. (For example, when I imagine someone holding a gun to my face, I don't think to myself, "Oh, whoops, I'm probably misunderstanding this person's intentions." In addition, there are many politicians who are likely never to receive the benefit of various deep pools of my doubt.)
In general, however, most of the people you come across mean you no harm or ill will. So even if and when you do have reason to doubt their good intentions, it's the right way forward to give them the benefit of the doubt regardless.
When we allow someone the benefit of the doubt, we give them a gift. The gift is a way forward that doesn't leave us pissed off, thinking badly of them, and disinclined to give them the benefit of the doubt in the future. Because, let's face it, if you've decided to mistrust someone, that's a decision that's hard to come back from.
Most of the divisions between people could be healed or at least helped by both parties simply giving the other the benefit of the doubt. Instead, we apparently prefer to assume people are idiots, or evil, or out to get us. Stop thinking that. Instead, assume good, and see what happens. How much worse can it get? What, really, is there to lose?
If it's in your nature to doubt and fear and mistrust, then my advice is to practice giving the benefit of the doubt more often. Instead of thinking, "Oh, that asshole just cut me off because he's clearly an asshole," try thinking, "Well that was totally uncool, but maybe he's not feeling well today, or he just found out he lost his job or that his mom has cancer. So maybe he didn't mean to act like an asshole." You not only get to drive on in a less singularly pissed-off frame of mind, but you've also flexed your kindness muscle in a very real way. You can drive on thinking, "And I'm not so bad myself."
My whole life I've been a champion for bright-siding. Accentuating the positive. Seeing the best in people wherever and whenever possible. I'm certain there have been occasions when it hasn't been deserved. But I know my life has been better, fuller, and happier because, generally speaking, I choose to trust that people are more good than bad.
Try trusting. If it doesn't work, I'll be sorry to hear it. But I'll just say again: try trusting.