Here's my shortlist:
1) Almost any sandwich on a crispy baguette- major damage
2) crispy tortilla chips or nachos eaten when drunk- I've had to pull out those pointy ends with a pair of tweezers
3) Panini's- Crisp on the outside, scalding on the inside
4) Those Totino's Pizza Puffs- They traumatized my mouth 30 years ago, but I haven't given up on them today- Hey they are still about $1 a box
5) Microwave sandwiches- especially those on a silver special microwaving tray- The instructions usually say to let it sit for 2 minutes after microwaving- I am too impatient- I wait maybe 12 seconds, and then I pay the price with a roof skin peel!!!