Mayo first, mustard second, horseradish sauce third, salsa fourth.
I suspect I’m one of the few on this planet who can’t stand ketchup. The only thing I use it for once in a blue moon is if I have to eat bad fries, but I’ve since learned I really don’t have to eat bad fries, so there’s that.
Does Tabasco sauce qualify as condiment? Lol. It will be my choice if it comes down to one! Salt/vinegar/spiciness into one. Can’t live without any.
Not a condiment person.
Mustard and sweet pickle relish on burgers, cocktail sauce for shrimp.
No ketchup since high school—can’t stand it.
I use balsamic vinaigrette on many things, so that’s my number one, even if it is a salad dressing.
Dai day Chinese duck sauce and deli mustard. I am trying to lose weight so I have given up all chicken but grilled chicken because they were just an excuse to use duck sauce. When I did Atkins, I switched from ketchup to mustard for burgers and I have just stuck with it. If I could only choose one, it would be mustard because of the calorie difference.
Balsamic vinegar.
Salsa for sure, I can even use it as a salad dressing. Very versatile. Yum!
I am quickly becoming addicted to balsamic glaze as a condiment - it’s a 10!
Tabasco absolutely a condiment!
Mayo. Then add spices.
Hellman’s mayo and Heinz ketchup.
In the 60’s my aunt used to ship the packets of Ranch dressing mix to us in the Midwest. We would mix it with mayo and buttermilk. Delicious. Now there are plenty of Ranch dressings with no buttermilk flavor at all. That just seems wrong.
My friends have been known to bring back a suitcase of Dijon mustard from France.
All you mayo lovers… you would do great in the countries of Central Asia. Kid sad she developed deep aversion to mayo because it was in everything, even in sushi!!! 
What is fry sauce?
Nando’s Peri Peri sauce (garlic), followed by whole grain mustard
@techmom99 a delicious mix of mayo and ketchup, plus whatever else sounds good to you. I’ve seen people mix in seasoning salts, relish, mustard, sriracha, barbecue sauce, you name it! It’s currently being marketed by Heinz as “mayochup” for whatever reason–anyone in Idaho, Montana, or Utah could tell you it’s fry sauce. It’s also what’s referred to as “secret sauce” by some burger joints, or, if you’re from Nevada, “Caine’s sauce”.
This house could not live without BBQ sauce - though we mostly eat out so I don’t need to have it at home. At home ketchup and (Dijon) mustard and salsa. Though I often just make my own salsa. I have made ketchup, but it’s a lot of trouble.
All you mayo lovers… you would do great in the countries of Central Asia. Kid sad she developed deep aversion to mayo because it was in everything, even in sushi!!! "
“Even” in sushi? Isn’t Mayo in most sushi that’s labeled “spicy” ? I’ve never had any kind of “spicy” sushi without mayo anywhere.
Mr. B says “horseradish sauce.” No wonder I said yes when he proposed. 
When I was a kid, I used to design parachutes out of old bed sheets (ha-ha) and test jump with them off the roof of our old barn… the huge horseradish bush served as my landing pad. The smell of horseradish brings out the memories of my childhood!!
Catsup/ketchup. You know horseradish sauce is horseradish added to catsup.
There is an article about ranch dressing’s origins in today’s Tampa Bay Times. Think 1950’s California “Hidden Valley Ranch” origins. Now used for a lot more than salads and replacing some other toppings.
I have always found it both odd and fascinating that part of the recipe for taco soup is a packet of Hidden Valley Ranch dressing mix (the rest is 1 lb. browned ground beef, 1 can each of undrained pinto beans, corn, & diced tomatoes, 1 small can undrained mild jalepenos, and 1 packet taco seasoning). I’m not sure what it does for the soup, but I’m a rule abider, so I put it in.
“You know horseradish sauce is horseradish added to catsup.”
Actually, in my neck of the woods, that is cocktail sauce. Horseradish sauce is mayonnaise/sour cream based.
What @doschicos said. Horseradish is a “white sauce.” Grandfather used to grind horseradish root, add a bit of vinegar, and that was his “special sauce.” For the sissies who could not handle the “good stuff”, he would add some sour cream.