I was in Saudi recently. We had some Norweigian engineers with us. Never been to the desert before and were worried about the temp.
We were talking about the weather --- going to be 110 (F, of course) outside.
They were in a complete state of panic until they figured out we were talking F. Then they still freaked because it was too hot for them.
Exactly, both systems are intuitive to people who grew up with them. I'm a little in-between because it changed over when I was about 8 or 9. But I know without the need for any mental conversions that 30 is verging on uncomfortably warm and 35 is uncomfortable, and 40 is pretty much unbearable (for a northern boy like me, anwyay, LOL).