As it often happens, positives and negatives go hand in hand, and nearly each item on this list confirms this idea. Tea is not different: it has its benefits, but at the same time it carries harm –and again, thanks to infamous tannins that discolors our teeth. If you think that only black tea lovers are exposed to such danger, you are wrong. Even if you are a green tea addict, your teeth may turn gray. But the encouraging thing is that the high-quality teas are less damaging for teeth, so if you spend more for teas now, you spend much less for your teeth in the future.