Ew. Ketchup. I only use ketchup for hotdogs and hamburgers. But for anything else, it’s mustard. Mustard = best. I never use mayonaise.
Drown everything in Ketchup! 
I forgot to mention, I use ketchup with fries. But I rarely have fries.
I have Mustard on sausage, sandwiches, and some other things which I cannot think of right now.
Edit: It’s odd that the Mustard choice has a red bar, and the Ketchup choice has a yellow bar. Mayonaise has blue. =/
Ew, none of the above plz.
You like none of them? =o
Heh, all of the above, often simulataneously 
Mayo with chips (fries for you US-ers), fish, often in sarnies too. Ketchup with all red meat, cheese, and of course, breakfast Mustard makes a bacon sarnie, which often makes up breakfast too- and let’s not forget about the daddy of all condiments, brown sauce, without which, meat of the swine would not be complete. X-D
mayonaise/ketchup/onions on fries
mayonaise on sandwiches
mustard/mayonaise/onions on hamburgers… (it rocks believe me…
Man, you people, you don’t know how gross that sounds. =X
What about tartar sauce? Cocktail sauce? Barbeque sauce? Steak sauce? Pickles? Relish? Sweet onions? I’ve had all of the above on hamburgers before.
Okay, but of main saucey type condiments, as I listed at the top of this page. I didn’t mean condiments altogether, just of those 3, which do you prefer?
Barbecue sauce bitches. Barbecue sauce.
Depends.
BBQ sauce for almost all chicken.
Ketchup for hot dogs, fries and burgers.
Mayo for sandwiches and lobster rolls.
Sometimes mustard for hot dogs.
I like mustardayonnaise and Mayostard.
it’s all good
Ketchup and mayonaise.
lessee:
Ketchup/mustard-cheeseburgers or hotdogs
Mustard/Mayonaise-Sandwiches, unless I have avocado on the sandwich, then niether.
Mayo/ketchup-omelet sandwich
ketchup: fries, and other things like fries.
mustard: corndogs.
mayo: ick, unless it’s used for tuna.
<a href=“http://yoga.at.infoseek.co.jp/flash/kikkomaso.swf”>SOY SAUCE!!!</a>
blood.
Barbecue sause, though mustard is useful in desperate situations, such as dining on campus.
This sounds so Earthbound.
Let’s all have delisauce.