Anyone trading should do the same. There's some psychoactive stuff in green tea leaves that tends to calm you down, make you more composed and rational. I've found it very useful for technical trading.
I remember reading that anthropologists suspect that it's the psychoactive qualities of green tea that led to the development of the Japanese tea ceremony and Zen Buddhism.
But I digress...
I'm a big fan of white tea (Chinese) from Fujian. it's been dried less, so there's even more goodies than in green tea.
Not sure about calm -- plenty of caffiene, but it certainly makes you more alive. There's a reason the British empire was built on tea imports.
I'll send some for 0.01BTC + p&p