Stress is minimal in this one, which is nice. There's the usual job-type stress; trying to please your employer, the lack of total freedom, having to roll your butt out of bed at a particular time each day (maybe evenings)...but as jobs go, this one registers pretty low on the anxiety scale.
You're making people happy (as opposed to a mechanic, on the other hand, who delivers mostly bad news), and, unlike a server in a run-of-the-mill restaurant, most of your customers are there to relax, take their time, and savor. You won't usually be rushed to work your magic. Unless they don't seem to be savoring.
The effect of the wine itself on the customer can either be a positive (chilled out, loose with the tips) or a negative (belligerent, disoriented). Coin toss here.