Why do we 'have to' attend Funerals?

Maybe this is a rant I don’t know. I hate funerals, and I know possibly we all do. However, some funerals are more complicated than others, consisting of bitter ex wives, ( a few) nosy family, and a few real friends thrown in. I am ‘done’ with sadness, tears and death. I have had too many over the last couple of years. However, I have been told I need to be there, to support my son. (As it’s his father). I do understand this. But has anyone had the same feeling? Do you feel forced to attend any function? because of obligation? How do you master the absolute anger at being forced if you do go? Clearly I need to do this before tomorrow.