Is it normal to wear flats without socks?
Yep.Totally normal
Yes, plenty of people wear flats without socks. No-show liners are an option if you want to reduce sweat or rubbing, but going sockless is completely ordinary.
Absolutely—flats are often worn barefoot, especially when socks would show. Some people prefer the feel, while others use no-show liners to keep their shoes fresher or help prevent blisters.