I'm going to block my sister on facebook
Why are you going to block your sister on Facebook?
She gives fantastic advice to my friends and I'm tired of seeing it.
Don't you think it's a positive thing that your sister is giving helpful advice to others? Maybe you can hider her posts instead of blocking her altogether so that it doesn't cause issues between you two.
I don't care about her feelings. I'm tired of her telling my friends what to do.
Before you block her, why don't you try to work it out with her? Maybe you can find a solution that makes everyone happy and won't hurt her feelings.