Like most human beings my feet heat up and sweat, not normally a problem for most socks as the they simply soak it up. However, the problem with these particular socks are when you remove them after a normal working day, most of the inside of the sock is left stuck to the bottom of your foot! therefore you end up leaving a messy trail of leftover, soggy sock material all over the place. I couldn't believe the mess and neither could the wife! Another bug bear is they're too tight at the top so dig in a bit after a few hours, I appreciate people of different sizes might not get any discomfort from this but you'd have to be pretty small because my ankles and calves are pretty average. I've literally had to throw them all in the bin as the hoover was starting to get clogged up with all the sock discharge.