Just compare" was supposed to do" with " should have done ", what is the difference？
They both seem like " I needed to do this thing but I didn't do it actually."
Someone told me "was supposed to do" is like " I was told to do something that I don't think I need to, then I didn't do it.'' and " should have done" is like " I also believe I need to do it , but then I didn't do it . ''
However, another one told me "was supposed to do" is more focus on " The thing you didn't do is not a big deal actually " and ''should have done" is like " You boss told you that you have to finish this task, which really matters, but you didn't do it "
I am confused.