Use a straw to sample from the glass
"There can be great joy in watching a bartender carefully measure out each ingredient, fill the mixing vessel with hand-cracked ice, go into an elaborate shake or elegant stir, and artfully pour their concoction into a cold glass for me. What ruins that experience? Watching said bartender stick a straw into the glass to taste it just before serving it to me.
"Don't get me wrong, I am all for straw-tasting drinks to ensure all the ingredients are in there and that the temperature and dilution levels are on point. But tasting the drink in the glass is like watching a chef plate a dish, then check if the sauce is seasoned correctly. Whaddya gonna do if it ain't? You already frickin' plated it! Straw-taste in the tin or the mixing glass, where you can still make any minute adjustments to ensure the $15 cocktail I am getting is worth every penny. Otherwise, you're just doing it for show." -- Joaquin Simo, Pouring Ribbons (New York, NY)
Lose their cool
"The mistakes I see bartenders make range from improper use of a jigger to making inappropriate remarks in front of guests. Our jobs can be so demanding, stressful, and fast, but sometimes you need to slow down and think about how it looks to a guest when you are yelling at a co-worker, or making rude comments. Even made in jest, an inside joke to you might lead to an uncomfortable situation for the guest. That guest will recall that feeling when making a recommendation or a return trip, and your bar may suffer for it. -- Abigail Gullo, Compere Lapin (New Orleans, LA)