Being in UK now, I can work out the time zones much easier compared to when I was working in Hong Kong. Asia is roughly 8 hours ahead of me, and US West coast 5 (?) hours behind me. The difficult is when I need to work out the specifics, particularly with USA having different time zones, having rubbish geography doesn't help! Then there's daylight saving time, who's changed and who hasn't? Another confusion. By the time I've sorted it out, they've changed again!!!