A) Don't talk about dreams that you only remember abstractly, like where you were in a dark place and had a funny feeling about something....this is kinda dull because everyone has dreams like that, that they don't remember very well. No one wants to hear about that unless they are a professional being paid to listen to you.
B) Don't talk about the dreams where you're in your underwear at school or you're falling and you wake up right before you hit the ground....again, everyone has dreams like that.
C) Don't analyze your own dreams for sexual content....everything can have sexual content.
D) Don't talk about dreams where something really weird and surreal happened, unless it's somehow specifically relevant to the person you're talking to. IT DIDN'T REALLY HAPPEN. So big whoop.
E) Do talk about dreams that involve specific people known by the person you're telling the dream to, doing something funny or uncharacteristic....your subconscious thoughts about the people in your life can be interesting to others, because it's like getting to peek at your id.
F) Do talk about your erotic dreams involving specific people...again, the details of your id might be interesting to others. Unless the specific person is Monica Bellucci or Brad Pitt or someone typical like that, in which case who cares.
G) Do talk about your nightmares out loud, not necessarily to make conversation, but because the process of letting the scary thoughts out into the conscious world will lessen the chance that your subconscious dredge them up as future bad dreaming.
H) Don't talk about the dreams where God spoke to you, or there was a brave new world where no one suffered, or where you had relations with a family member (exception to F, above). These are all kind of creepy.
I) Do talk about dreams where something bad happens to someone you know; some would disagree with this, because I believe there are some superstitions that say if you dream someone's gonna die, they're really gonna die. But I think it's a good conversation piece because maybe talking about it will ward off the chance of it happening. Plus whenever a friend is hurt in a dream and I wake up to reality and they're fine, there's a sense of relief and refreshed love and appreciation for that person, and I think telling them about it is a sort of small way of saying that you care.