So, for tea at least, and green tea in particular, water temperature is actually very important. This is often overlooked by people (at least in my experience in America). I've had many friends who claimed to hate Green Tea because it is bitter. But they changed their minds when I brewed them a cup and explained that it is important not to burn the leaves with hot water and then over-steep the tea---rather than boiling water you often want water considerably cooler, say 150-180 F, depending on the tea. You also don't want to steep for too long (often just a minute or two, again depends on the tea).
When I was younger I used to hate bitter tastes, I used to shiver when I tasted some. But at some point the only thing to drink at our office was the tea, and sugar ran out quickly so I adjusted. I barely feel bitter taste now and only if I put a tea bag in cup of hot water and drink it after a while without taking out the bag or stirring it.
For black tea too, temperature is really important (it should be boiling). Never order black tea in the States, you'll receive a teabag along with container of tepid water.
