The word "should," Evil or Not?

I recently learned about the word "should" and just what a bad word it is to have in your vocabulary. We've all heard the expression, "Saying you shoulda, woulda, couldas," especially after something happens. However, I learned recently that the only thing the word "should" does is place blame/shame upon yourself. Either you feel guilty about something you did or didn't do, or this word "should" keeps you focusing on things in the past and not focused on your future. You need to focus on moving forward and not wallow in the past.