Once in Portugal as a teenager I basically did a cricketers two swipes of suncream on my cheeks as though that would be any sort of protection. Got burnt pretty badly aside from those two smears, looked like a weird panda.
The other time was on a Caribbean cruise, went on deck the first day feeling slightly seasick and sat in the breeze for about 15 minutes - felt much better. Only later realised that I’d burned to a crisp - it hadn’t even been sunny outside, it was overcast! Mrs HYG had it much worse, actually looked like someone had pressed an iron on her, it went all scabby, one of the waitresses gave her a pot of yoghurt to put on it as it apparently helped.