Why does coffee taste better out of your own mug?

I'm really not sure about this, but I suspect there is a dissertation out there somewhere about the following topic:
Why does coffee taste better out of your own mug?
I LOVE coffee! Can't get enough (though my cardiologist thinks I should try to get enough a lot less frequently). In our lives at the moment, we are living with my in-laws until our house in San Antonio sells (and, seriously, THANKS BE TO GOD we have a contract on it!) and I've been drinking the same coffee I usually drink out of their coffee mugs. It's the same product (this week I've been rotating between finishing out my Starbucks Christmas Blend and the Dunkin Donuts original, which is today's choice), the same water, but the mugs are not my own. That is, until Christmas came and I got a mug as a gift from my folks. I don't understand it but the coffee tastes better! Obviously, there must be some sort of neurological issues at work here but I find it frankly fascinating.
The coffee was fine when it came in other mugs.
The coffee was better when it came in my own, new mug.
The new mug didn't even need a break-in period, it was just instantly better.
Hmmm.....