The only thing I have to have is lipstick. And I have duplicates of the lipsticks I wear stashed in different purses, so I never end up forgetting to take it along. Which I rarely do, but it sometimes happens.

Another one for team eyebrow pencil. And I also feel naked without mascara. I, too, have stopped at the store because I forgot to put on mascara -- twice in recent memory. Supermarkets have very weird brands of mascara.

For this reason alone, you never want to look inside my handbag! I like to think that it doubles as weight training for my shoulder....

PS: Mine is lipstick. And sunscreen. I'm like a vampire if I'm out in the sun without it! (ETA: the avoidance of bright lights, not any sudden desire to suck blood.)