It always annoys me when you feel the blast of hot air just after the cabin lights have been dimmed -it seems that some CSDs think they'll turn the lights off and put the temp up to send everyone into a deep sleep. I'd much rather have a too cold cabin than a too hot one -you can always get a blanket or put a jacket on, but it is more problematic to take clothes off! On the other hand, for every person who thiks it's too hot, there will be another who complains that they are freezing cold, so it's a bit of a catch 22 for the crew. I'd personally say 20-22 is a more realistic range than 23-24 -and if I were crew I'd offer cold passengers a blanket and advise colleagues to wrap up warm if they are cold. A hot cabin is the absolute WORST experience because it makes you feel sick and gives you a massive headache.