Look for the happy people.
Happy people are more productive and better to be around. I don’t have the research at hand, but this is true in my experience.
Happy does not mean, giddy, laugh-at-every-little-thing people, to me it means people who are satisfied, who somehow communicate that they know that everything is not ok, and they are ok with that.
Happy means satisfied, in a good way. Dissatisfied is the realm of a constant, “I wish things were different,” approach to the world.
One can work to be “better” and not be dissatisfied, for sure, but meanwhile I aim to be comfortable with the process. It’s a happier way to be.