In the dream, your friend who is normally cautious, wants to try something new (smoke pot). This could be a message from your unconscious that you need to be brave about something.

A dream about dancing with a stranger can be a sign that you want to start a relationship or you want a relationship you are already in to go further, so the attractive guy asking you to dance can mean that either 1) you're looking to meet someone new if you aren't with anyone already or 2) if you're already with someone, you want that relationship to go further.

The dream could be telling you that if you want to make it happen, you have to be brave and take matters into your own hands.

It's interesting that you felt sad when you woke up, even though it was a good dream. Did you feel disappointed that you don't have someone like that in real life. That could also be a sign that you need to make a change.