Pessimism can also simply mean you say no to a lot of stupid things by default, and only adopt new ideas that pass a little gauntlet of validity. That can be a

Pessimism can also simply mean you say no to a lot of stupid things by default, and only adopt new ideas that pass a little gauntlet of validity. That can be an efficiency win through many different mechanisms. You can also be pessimistic and optimistic at the same time in different contexts or scales. I pessimistically assume every sales pitch is something better for the salesman than for me. I optimistically think that humanity is on the whole more good than bad, and more progressing than not.