I agree with much of what you’ve written, with a caveat about spicy food. I’m fact the vanilloid receptors which capsaicin binds to is damaged over time by exposure to spice. In other words the more spicy food you eat, the less sensitive you will be to spice on a physical level. Where spicy food is concerned, it’s more like opiate addicts requiring higher doses; it is a form of acquired tolerance, albeit on the tongue rather than in the brain.