Partly, it's sadness, for them.
Partly, it's frustration, because I work so damn hard to keep these students on track, giving them what the literature calls "all the tools they need to succeed."
Partly, it's puzzlement, because when we had our most recent one-on-one conferences (this is a conference-heavy class), they all walked out seeming to have purpose and confidence.
Mostly, though, it's the sure knowledge that, when I stick to my guns and refuse to grade late work, as laid out in the syllabus, their shame will turn outwards to anger, directed at me, and I'm gonna get hammered on the evaluations. By fully one-third of my class.