It can be very embarrassing, especially if it happens at a business meeting or social event. When it does happen, you may wish you could crawl into a hole.
What are we talking about? When you raise your arm for something and show off an unsightly deodorant stain on your shirt, blouse, or other items of clothing. You know people notice because their eyes are drawn right to your armpit, and there is never a hole close enough to crawl into.