Air Conditioners, Hong Kong
Not having one always with me on my first two days in Hong Kong made me get a cold....
Air-conditioners all over Hong Kong tend to be a little too cold, even for my standards. So try to keep you warm indoors and take it off outdoors... you will survive without such a cold at the end.
Expect to get water droplets falling on you even if it's not raining. This happens especially as you walk along the side walks along the street shops. Most of this water comes from the condensation of air-con units above you... or at least, that's what i'd like to think... ;p
Something else I thought was very different about Hong Kong was the fact that you had to look out for the airconditioners that drip on your head down most of the streets in Hong Kong! ;)
By the end of the first day we learnt to look for puddles on the ground to know where to dodge...haha!! You'll learn it very quickly too...
The by far most annoying thing about HK is the ever dripping Air Conditioners. Every where you go, you get splashed with drips of water from the window mounted Air Cons.