I've no opinion to offer, but thinking about the thread title...
- Straight is pretty easy, though the Miss, Mrs. Ms. thing can be sticky, along with hyphenated names and different surnames, wife and husband
- Gay is a little challenging
- Lesbian also challenging
- Bisexual and Transgender, even if you know roughly what you are dealing with in a given situation, pretty intimidating. More so when you really don't know.

Maybe we just need to be flexible and understanding. Respectful.