This answer assumes that you are asking about ideal brewing temperatures, rather than ideal drinking temperatures. The latter would, indeed, vary from person to person.
The ideal brewing temperature varies between types of tea. I have taken the following from ask.com, but the particulars are found elsewhere, too, like here:
These steeping times are only approximate, and you should adjust them depending on your own personal tea taste.
Black tea - Black is the most robust of the tea varieties and can be brewed in truly boiling water, usually steeped for 4-6 minutes.
Oolong tea - As to be expected, oolong tea falls between green and black. The best temperature is around 190F. But oolong should be steeped longer than black tea, for around 5-8 minutes.
Green tea - You will need to be more gentle with your green teas. The water temperature should be around 150-160F and only steeped for 2-4 minutes.
White tea - Another delicate tea that should be treated gently. Water can be a bit warmer than for green tea, at 180F. You should let it steep longer though. At least 4-6 minutes.
Rooibos tea - This red herbal tea from South Africa is very hardy stuff and should be prepared with fully boiling water, just like black tea.
Most herbal teas - With so many different herbs that can be used for herbal tea blends, there is no way to give any temperature or steeping guidelines with any accuracy. Most herbs can be brewed in boiling water and steeped for about 5 minutes. You might need a bit of trial and error to get the perfect cup.
If you don't have a thermometer handy, you can tell the water temperature by watching the bubbles. Small bubbles will float to the surface of the water 160-170F, and you'll see strings of bubbles from the bottom of the kettle at 180-190F. After that, you'll have a full rolling boil.
Best Answer
Chai masala variants may be boiled that long or more – they do contain black tea, but also spices (where the boiling is needed, to extract the flavor from whole spices). The tea decoction this produces does contain all of the bitter compounds, sure – but it is mixed with spices, diluted generously with milk and sugar, and becomes a palatable drink that is nevertheless very different from the coolly and weakly brewed variety you seem to be familiar with.
In fact, it is even possible that the tea was plain black tea, brewed very strongly. Served with plenty of milk and sugar to balance the bitterness, milk tea is a cultural variation. Think of it kinda like coffee, if you want – it is bitter, but it is expected to be – and the tea can be doctored to make it work for the drinker.
Tea can be served in lots of different variations, and none are more correct than others – just like some teas are brewed very light and almost flavorless (japanese green, and 15 seconds per brew), and others are brewed to death and sweetened to balance (southern style sweet tea), some are served with milk, sugar, or lemon, and still more are served with salt or butter (tibetan). Boiled milk tea or chai are brewed to death, to extract all the flavor, and served sweet and milky to balance the strength and bitterness – and a weakly brewed tea would be tasteless and vanish in the expected fixings.