When we launch a new product, like the StellarGold series, we always spend time doing an in house beta test. Staff members from all departments get to take home the gear and play with it for a few days.
Their mission is to find anything out of place or not working as intended. It's easy to miss something when you're the engineer that's labored over the product for months.
One the most rewarding reactions we get is when our tester reports back they forgot to look for flaws. That within moments of the music playing they were swept away into musical bliss.
There's foot tapping as a good indicator of liking gear, but those times you suddenly forget why you were here and what you were supposed to be doing...
That's the biggest compliment of them all.