You like to tell people the truth, but seldom care if they really want to hear it. Although it’s clear that your intentions are the most positive ones, still hardly anyone would like to hear a phrase like “You’re so pretty for a plus-sized girl!” or “Do you have any health problems?” Even if people you’re talking to are not perfect, they don’t want others to emphasize this!
Try to read more books and watch videos about the rules of etiquette if you want to stop shocking people with your words. They will give you a set of established rules, and it will be much easier for you to follow them if you know what to do in this or that particular situation. Keep it in mind that if a person doesn’t tell you that you sound offensive it doesn’t mean he or she thinks differently!