German potato salad (not too sweet) FTW. But since that's not a choice, I'll go mayo but I like mustard too.
Maine has a good swing for a pitcher but on anything that moves, he has no chance. And if it's a fastball, it has to be up in the zone. Basically, the pitcher has to hit his bat. - Mike Pelfrey
Mustard for me, easy. I think mayo is probably the most disgusting substance on Earth, although canned tuna is close. And I love mustard, I even use it to dip fries in sometimes.
Luckily my wife feels the same way and she makes a killer potato salad with some mustard, grilled onions, and bacon.