I learnt to dive in warm water and stayed in warm water for about 200 dives. After that, it was cold water, generally low visibility drysuit diving. I found it a challenge at first and was pleased with myself that I could manage in those conditions and with the extra gear required. Did about 200 dives in cold water. It certainly made me a better diver. Now I live in an area with temperate seas (14-21 degrees C). I prefer warm water diving, can tolerate the temperate stuff, but can't see myself ever doing proper cold water diving again.