You can't be mad at people for failing you

Whether it be employees,family, friends or co-workers you just have to accept that you can't exactly expect someone to do exactly what you want them to do . You won't ever be completely aware of everything's going on in their life,you won't ever share all the information with them,you can't predict what's going to come up in the future so like even if you tell someone to do something explicitly,you should still know that they might not do things as you expected.

I know most people know this already but I felt like saying it. Get disappointed but not mad.