Believe it or not there is a real life version of this. Probably would be classified as a 'Dark Side' use of The Force.
I learned this while waiting tables. For those who don't know one of the jobs of the waiters at most restaurants is to upsell. The waiter can be motivated to do this for many reasons but the most basic reason is that most people tip based upon a percentage of the total check. Therefore bigger checks lead to bigger tips. Of course the restaurant management is generally pleased by large checks too.
So, during my time as a waiter it so happened that management devised a plan to sell more margaritas. It was a simple plan: have a month long contest between the waitstaff to see who could sell the most Margaritas. Prizes, cash and others would be given at the end of the month.
While rolling out this contest to the waitstaff management had one of the older staff pass on some secrets to us kids. The only one I remembered was "The Jedi Mind Trick".
Okay big buildup for this sadly simple payoff:
The 'trick' was to simply arch your eyebrows while nodding slightly and suggesting a course of action. For me the novice tequila slinger, I would simply ask "Would you like one of our Top Drawer Margaritas?" while performing aforementioned physical cues.
What was amazing was how well this worked. I sold something like 85 margaritas that month. Second only to my instructor the Dark Jedi Master (yah yah so that should be Sith Lord or something, oh well).
This probably only worked so well since people generally go into a restaurant expecting their waiter to help them by suggesting particularly good food or drink. Perhaps you'll notice this 'help' from you waiter at a future eatery visit.
Regardless of what you see or suspect, if the service is good tip at least 15% of the check. I can assure you've they've earned it and it's just good Karma.
Do I still use this trick? Only subconsciously.