Makeup is one of my biggest interests, however I wake up late a lot of the time and don't have time to put it on. It's fun to be creative and almost create art on your face, and to show it off for a day.
The big physics principle behind makeup is trying to combat the force of gravity and using friction to help the makeup apply.
All the makeup on your face is applied with some amount of friction helping you out. Whether you're applying lipstick from the tube or using a brush to put on eyeshadow, you're counting on friction to put that stuff on your face.
You also count on that force of friction to keep your makeup on your face throughout the day. If there was no friction, the makeup would fall right off your face.
(Below are some selected favorites from my collection which all demonstrate this physics principle. Also, my cat Mia is a diva and had to be in the photo.)