Do you go with just 1 condiment on your burger, none, or mix & match?
 
I myself am a Mustard guy through and through, no matter if it is a burger or hot dog. I don't care for ketchup or Mayo on a burger whatsoever, don't know why but I just can't stomach either when on a good old fashion burger.

Depends on my mood.  I like Lowry's Season Salt when cooking the burger, muenster cheese, and ketchup.  Sometimes A1 is pretty good, and other times I like mayo.  The only time I use mustard is on Vienna beef hot dogs.

I'm weird. I like BBQ sauce. I'm very plain when it comes to food. My go to is usually bacon, cheese, and BBQ sauce. I get ketchup at In and Out though.

Burger sauce! I don't know what it is but it tastes of mayo,ketchup and mustard all mixed together! It's beautiful! Other than that I'm a complete mayo lover!

It's all about the ketchup, if other toppings count as condiments, then I am also a fan of the finely diced onion.

brown sauce (HP of course)  all the way, fruity/spicy/sweet/vinegary brown sauce on a nice rare burger on a lightly toasted bun, hmm.

Mayo is nasty and just adds more fat to an already fatty food. Personally I like ketchup, mustard, and dill relish. I also hate American cheese and prefer a sharp cheddar or a nice pepper jack.

I don't consider cheese a condiment when it comes to burgers. I use ketchup, mustard, and mayo. The variation comes in the type of mustard I use. Also tomato and lettuce if those are considered condiments.

Nothing wrong with the Ketchup + Mustard + Mayo trifecta.  However, I'm known to go only BBQ sauce if I'm feeling sassy.

Ketchup only dude, mayo is one of the worlds most disgusting condiments.

Usually ketchup and mayonnaise. Sometimes I'll throw some mustard in there. 

Ani...mal... style?

My stepmom would eat spoonfuls of Mayo out of the jar. That right there is enough to make me not look at the stuff without getting nauseous.

Practice a safe lunch, use condiments.

bit of A1, maybe mustard?

 
dijon and catsup :-d

Ketchup only, anything else sucks. I mean when Bruce Willis hates mayo on burgers, you better not use it. 

It depends on my mood, but whenever I go to 5 Guys I usually get... 
Double Patty 
Double Cheese 
Bacon 
Lettuce 
A1 Sauce 
Jalapeños  
 
But one of my favorite burgers is the Spicy Baja at SmashBurger. It is... 
Patty 
Guacamole 
Pepper Jack Cheese 
Jalapeños 
Onions  
Spicy Chipotle Sauce

Fried egg

I always get ketchup, mustard and tomatoes...after that, depends on my mood and what's available.

" Ketchup/mayo combo. "

For me ketchup is king.

Ketchup and the good BBQ stuff. If I'm a little daring, toss some sort of sweet/sour sauce on it.

On a run-of-the-mill fast-food burger: mayo, ketchup, yellow mustard, dill pickle slices.
On a family-BBQ fat, juicy burger: mayo, ketchup, sweet relish.

ketchup + Franks = tasty.

ketchup & mayo mixed together, maybe some bbq sauce too.

Ketchup and mustard.  The two flavors counter and compliment each other perfectly.