American mayonnaise in jars can be good, but Japanese Kewpie mayonnaise is "the best mayonnaise on the planet," says tonbo0422. What's special about it? "I lived in Japan for five years and was surprised to learn that the 'secret' ingredient was ... rice wine vinegar!" says tonbo0422.
The rice vinegar is important, says FoodFuser—and also the MSG, which rounds out the vinegar's characteristic flavor. "And on a more tactile level, it may be that sexy little half-liter squeeze bottle that lovingly yields to your hand and also fits into those tiny home refrigerators, and that fine nozzle tip that allows one to make some really cool designs on their okonomiyaki," says FoodFuser. "Every mayo lover should experience the supple flexibility of the squeezed Kewpie bottle as it sends forth its tasty stream." And, adds FoodFuser, if you can't get Kewpie, you can add rice vinegar and MSG to regular mayo in the jar—it really works to re-create the flavor.
Discuss: Kewpie mayonnaise—why is it so good?