I have very strong views about sinks and faucets. For example, I am a big fan of the one sink kitchen sink (I have no use for divided sinks). But this is not really about sinks, it is about faucets.
Throughout the UK (it was this way when I lived in Scotland, too, in 1990-91), all the sinks have two spigots - one for hot and one for cold. Some older homes in the U.S. have these separate water spigots but most updated bathrooms have one spigot - they might have two handles, but one spigot.
I just don't know and have never learned the best way to wash one's face when you have the 2 spigot faucet. The hot water is coming out of one while the cold water out the other. So here are my approaches:
1. Try to use just the hot water before it turns really hot. [this usually does not work so then I must move on.]
2. Cup my hands under the cold water and then under the hot for mixing and then splash on face. Usually I still burn my hands a bit with this method.
3. The third and least clean is to put the sink plug in, let the water join in the basin and then just rinse with increasingly soapy water.