A neat little 6 minute video I stumbled across where a researcher discusses expectation biases in both pain control and beer.
His story about vinegar in beer reminded me about the study where they took expensive wines and sold them for cheap, and cheap wines and sold them as expensive, and both at their real prices. What mattered more than the sort of wine was the price tag. The higher the price, the more people reported enjoying it, it's quality, etc. We expect a 100 dollar bottle to be great, and a 2 dollar bottle to be questionable so much that it takes amazing push to get over that hump.