Depends on what I'm doing and the wind. If I'm cycling to school I usually roll up my sleeves and pants if it's above 5-10° C, and I usually wear extra clothes if it gets below 0° C.
...But if I'm standing still or walking around at 5° C I might freeze, and if it's windy 10° C can easily feel cold.
As for hot I definitely don't prefer temperatures above 25° C. ~22° C seems like a good room temperature imo.