There was a practice that some meditators have done, and if you want to try it you're most welcome, but it's not everybody's cup of tea. The practice is to have 2 plates when you're eating, take a spoonful of food and chew, chew 20 times. Stop. Spit it out on the other plate - I said it wasn't everyone's cup of tea - and then you "eat" the entire meal in this way. Then you do the same thing again, chewing 20 times and spitting it out. You do it until the amount of food is so small that you just swallow it all because you're swallowing as you're going along. It's very interesting, with that experiment the food is absolutely neutral after a while. It doesn't matter whether it was pleasant or unpleasant, it is absolutely neutral. It's a very interesting experiment.
So, yes, our awareness is on many levels, what we call "pleasant" or "unpleasant" certainly can change over time, and certainly does change when you're doing the same thing over and over and over and over. The loved one coming and stroking your arm, a classic example, it certainly does change. It doesn't go to neutral very easily, it goes into pain, but in general when you repeat something over, and over, and over, the happy thrill of it being real nice, or the upset feeling of it being not so nice, often moves into the middle because it's just simply what we're doing.