Arrogance is a weakness

Being arrogant is indeed a weakness because sometimes just paying attention and giving a little thought may bring benifits. If someone is telling you something you already know, my advice is to just listen to him/her anyways. This is because sometimes we know something but the person telling us the same thing might know something deeper. So by listening to them despite knowing, may sometimes let you understand further. If you already know what the person tells you at the end of the conversation, then good for you. You know as much as the person. If not, then good for you too because by listening to them you've learned something =D