It's easy to blame someone thinking that they're wrong. It's easy to question someone thinking that they cannot answer your questions. It's easy to corner someone thinking that you're witty and sensible.
But it's not always right thing to do. Until the reasons and motives are known, doing these will just hurt them, not make you right.
Never take someone's love, time, care, and concern taken for granted. And remember no one will give theirs to you no matter what. Just don't take advantage of these. When they know it, it breaks them from inside.