Often used by your girl/boy-friend as a surrpetitious excuse to see less of you; really may mean "fuck off."
"I think maybe you are coming over too often when I'm busy. We need to start thinking about spending more quality time together, where we can interact more and talk."
Translation: "Fuck off and die in a fire. I'd rather watch these stupid reality TV shows than spend a minute with your sorry ass."
Sex, usually when it happens infrequently due to life/work constrictions.
We've been so busy, we haven't had any quality time in over a month.