I'm not picky about this and I'm willing to try most condiments. There was one in a korean restaurant I tried recently that was pretty great. Sadly, when I asked for more information, they said it was just a house special.
It could be because I've been staring at a screen for literally 12 hours today but when seeing this thread all my chakras were unblocked and a singular image formed in my mind:
all that aside, mayo is nice! But if I eat too much of it I feel really sick. I like sweet chilli, ketchup, mustard and horse radish as well. SOY SAUCE. I almost forgot that.
The only condiment I get much use of at this point in time is mustard. I have a preference for the spicy brown variety, and I had honey mustard at a restaurant a few years ago and that's nice, but plain yellow is fine too. My diet has been in a state of flux for a while and I lean more toward less processed things, so I'm still navigating other condiments and seeing which can work for me.
My favorite is definitely mustard, though I also like ketchup. For me, condiments are always a must when I'm eating French fries cuz they taste too bland without any sauce. I also like bbq sauce, but not when it tastes too sweet. I really dislike the sweet flavor of the newer bbq sauce from Wendy's and miss the original one. Besides that, I like the taste of relish on hot dogs and I think chutney tastes amazing with Indian food.