One should always be ultra-polite when asking for any favor, of course, but you should act especially humble and unassuming if your request involves anything other than "run-of-the-mill" stuff. Most people will usually understand that life is not always easy or convenient, and so if you ask su-u-u-u-uper-nicely (and of course, try to only request help/favors when you really need it), it is amazing what people may do/allow for you.

"My visit home turned into Bisexual Groundhog Day. My mom acted shocked when I told her I'm going to Pride next week, so I had to come out to her as bisexual AGAIN."