I don't really have that problem too much, but I would find it a rude thing to say. However, if it's something you don't personally have a problem with then I would try not to get offended by it. Hard to offend someone when they are happy with whatever "flaw" someone thinks they are pointing out. For instance, I speak my mind and rarely hold anything back. Some people would find that flawed, but if anyone ever told me that I would just laugh and say "Sorry, it's who I am. Deal with it." We should never have to change for anyone else, we should only change if we, ourselves, have a problem with something we do or something in our life. Just my two cents.