My mouth doesn't have the receptors to detect capsacin, the chemical that makes spicy food burn/hot. I can eat the spiciest food imaginable and it will not burn my mouth at all.
That said, those receptors exist in other parts of my body. Very often while I'm sitting on the toilet I'll realize my dinner the previous night was particularly spicy.
Also, after more than 1/3 of a century of eating spicy food indiscriminately, my stomach lining has taken quite the beating.
Rather than "god damn" I usually say "gods damn". I'm not religious at all, but I'd rather someone mistake me for a polytheistic pagan than a Christian.