5. You use a lot of interjections and speak too fast when answering questions.
A lot of interjections and pauses are signs that someone is worried. So if people speak very fast or very slow, this is alarming for flight attentions. This is what people hiding their true intentions do. Of course, nobody expects you to speak like a news anchor, but if you look suspicious and speak so that you are hard to understand, you may get some extra attention from flight attendants.
6. You look like a Greek god.
If a flight attendant is smiling at you and looking at your strong arms it is, most likely, not because you are very handsome. In fact, she has identified you as a potential source of help. You might be useful if there is a loud or troublesome passenger, an old lady with really heavy bags, or if it is necessary to open the emergency exit. Flight attendants are as happy to see big, strong people as they are when there is a doctor, a pilot, or a rescue team professional on board.