I'm going to start this off with a question: how do you decide whether or not to capitalize the beginning of a line? You seem mostly to be following the punctuation, but there are two deviations from this, right in here: clutching cutlery, / Smiles stoic. / You and I maintain an appearance of indifference, / Prideful and polite. Was it accidental, or was there a reason?

I think that the first three lines of this are the most powerful. It really sets a mood, and shows an interesting degree of mutual understanding. They both know that the date (?) is not going well, but they still try to pretend. That's one element that's a lot more clear in this poem than in Diarrhea, and it's excellent.

The line You and I maintain an appearance of indifference is a bit cumbersome, and I think that it's length draws a reader's attention away from the meaning, that they are striving merely to show indifference, rather than to act like they are having some excellent time. Maybe try breaking it up, like You and I maintain an appearance / of indifference. Of course that might lead to too many lines that are short, and you wouldn't want to put prideful and polite with indifference or it will seem as if it is the indifference that is prideful and polite, rather than the people.

I like the lines in this I chatter like teeth in winter, / my nervous, grating voice mimics / the sound that fork makes on your plate. much more than the counterpart lines I rattled on—my high-pitched voice / mingled easily with the fork-meets-plate sounds of the dining room— from Diarrhea; there is better imagery and I think it's good to make the fork-on-plate sound a little more personal (it also serves to clarify how disengaged the other person is - presumably paying more attention to the food than to what our protagonist is saying - without resorting to line talking about things neither of us cared about. which can pretty much be assumed).

All in all this is definitely a better poem than Diarrhea. I like that it shows the other person in a slightly more sympathetic light. And it just establishes the feeling a lot more clearly. I really found only that one thing that I would change, and even that might be best the way it is.