1. A metaphorical food used to describe something that is outrageously angsty, Emo, Gothic, or gloomy in nature.
2: The feeling in your stomach when you feel miserable (i.e. you feel like you've eaten an "Angst Sandwich).
1: Dude, Interview with a Vampire was such an Angst Sandwich!
2: I feel terrible after my girlfriend told me she was dumping me, it's like I've eaten an Angst Sandwich!