I didn't realize until my mid 20s that having a house without pictures and wall hanging is weird. It was also when I learned that if you don't have enough lighting it makes a home feel like a mausoleum.

The answer as to what a person should put on their walls depends on how based a person is or how much they don't care about what others think.

If you want to get non-traditional with it, hang up movie posters, collages, video game posters, etc. Whatever you like and like to look at.

If you go traditional and normal, then art is a fantastic idea. Go to your local thrift store and find old art that they have. Local estate sales are also good.

Personally, I love to commission a painting or two from the artist themselves. Etsy and fiverr painters love to make custom art of whatever you want if you have the money. You're looking at spending anywhere from $10 to a few hundred depending on the size you want.

It's always fun having a painting of your pet remade in the style of Edvard Munch