My gf says this. But when I eat spicy food, it doesn't interfere with the taste whatsoever. I also love the taste of really hot coffee when I'm eating something spicy. Something about the double burn really enhances the flavor.

Yes, food that's too spicy for a person can definitely distract from the other flavors and if way too hot even cause numbness, but it's not actually chemically burning your taste buds. It's just tricking one particular type of heat receptor nerve to falsely detect heat. The numbing effect can happen when those nerves are over stimulated, which triggers an inflammation response as if you had just gotten a real burn. Those nerves do get de-sensitized with exposure, but since it's only one type among several different types of heat sensing nerve, it doesn't damage the mouth's ability to feel actual temperature heat. Only mammals have that particular type of sensory nerve, so birds, reptiles, etc. are completely unaffected by it.