Pay attention. There are two reasons to eat: to sate hunger, and for the pleasure of the food. Dinner, however, dinner is not simply a way to spend time with someone, but to invite them to share in satiation and pleasure. Mutual pleasure being, of course, greater than the sum of it's parts.

[ The manner in which she speaks is a very subtle mockery of Sherlock when he solves a case. ]

I'm not going to tell you to have dinner with me, Mr. Holmes, because then you'd have to obey me. But I'm not going to ask, either.

[ Irene doesn't tend to ask for things. ]