Note that this list is in no way exhaustive but is merely a guideline for the most common scenarios.

• If the ratio of crust thickness to topping thickness is greater than or equal to 5:1
• If the pizza slice is at least twice the size of your face
• If at least 95% of other people in the room are doing so
• If you are pretending to be polite/clean for various reasons…
• If you have no teeth
• If the pizza burns your hands but not your mouth (unlikely – possibly due to disease….)
• If you are wearing gloves
• If you are somehow able to eat more pizza per second by fork and knife

If you often find yourself in the above situations, the fork/cutter is a must. Found at the aptly named site: Stupid Idiotic.