The pessimist's glassware collection almost functions like a 'Do Not Disturb' sign, allowing you to drink peacefully in your gloom. If people are smart, they'll leave you alone -- because interrupting a pessimist mid-drink is a pleasant experience for no one.
Mirriam-Webster defines pessimism as "an inclination to emphasize adverse aspects, conditions and possibilities or to expect the worst possible outcome." Or, even more accurately, it's believing in a "doctrine that reality is essentially evil." In other words, life's a b*tch and then you die.
The most important distinction we can make between people is whether their existential glass is half-full or half-empty. If you're erring on the side of empty, then you'll appreciate this collection.