Why do we drink tea? Tea as we know it; it’s nothing but a history of imperialism & industrialisation. Instead make your own tea; fresh picked guava leaves,mango ,banana leaves etc boil with spices like cinnamon, ginger, cloves etc will do the magic.
Discussion
and then your trees die because you picked all the leaves.
however, black and green tea have a bit of caffeine. i guess that's one reason ppl prefer it.
i personally don't drink tea, but mix guarana powder into water or juice to get my caffeine boost. it doesn't mix well though; you always have to stir before taking a sip.