Think I’ll have my two penneth on this one. I used to have a touring holiday of about 2-3000 miles in Europe every year for about 15 years. Sometimes the temperature was well over 30 degrees and you could be stuck in traffic in a city with your leathers on and the bike fan blowing hot air onto your already sweaty knackers. Now I think that if I hadn’t taken off my layers I could have collapsed through heat exhaustion. With gloves on, your hands get so hot that they start to lose control and you make daft mistakes. I can’t condone it in high speed riding as the wind cools you to a large extent (and your injuries would be worse), but slow speed in traffic I think is OK. Bear in mind you could be more dangerous to yourself and others when you have no control of your bike.
I often wore shorts and sandals (and no I didn’t wear socks!) for short distances but you’ve gotta watch that exhaust pipe!