In Tennessee, the server and establishment can be liable if they serve too much and the consumer later goes on to be involved in an alcohol related injury. I don't believe there is an actual definition of how much constitutes too much. However, keep in mind that in late August 2009 Ruby Tuesday in Tennessee was found liable for over-serving a customer who later assaulted a man and was ordered to pay $10 million for serving the customer too much alcohol. Ruby Tuesday denied that they served too much alcohol but it was the equivalent of 19 beers over a 2 1/2 - 3 hour period of time and he appeared visibly intoxicated in the surveillance video. The server in an interview claimed that it may be too much for some people but not for everyone.
I am not saying that you were intoxicated after one drink, but it is possible that some servers and establishments in Tennessee are extra careful as a result since the metabolism rate is considered one drink per hour.