Color can be intimidating to some home owners. In reality, a little color can make the biggest and best changes in a room, stair way or hall way. Be it an accent wall or the entire room!
There are warm colors and cool colors. "Blue" a cool and calming color. Like being outside looking at the sky or water. "Red" A bold but warm color. It can make a large space feel more cozy. Have a tall ceiling? Room feels big and cold. Red walls can bring that ceiling lower and warm up that space.
Personal inspiration is the key. What color do you want to live in? Get some throw pillows, and space rugs in a certain color you are thinking about. Do you hate them after a week? Then that would not be your color!
I think the main thing is, dont be afraid to try something new on your walls. White can be so drab day after day. Bring some sunshine to those walls!