Truth be told, I rarely will go out the house without my toenails painted. It's a thing. Regardless if I'm wearing sandals/peeptoes or just sneakers. To me personally, It would be like going out without brushing my hair or teeth, or going out in dirty clothes. I think feet arent very pretty to begin with, so they need a little extra love. It just makes me feel more like a lady.
As for colours, just about any colour, sparkles, design or finish I feel like. sometimes I'll match it with my clothes, sometimes I'll go for whatever. Lots of reds and french tips, but also blues/greens/pinks/yellows.. pretty much anything.