I keep getting press releases that announce sirarcha (chili paste sauce) with mayonnaise is the new taste sensation of 2015. While I don't disagree that sirarcha mayonnaise (or wasabi mayo or chipotle mayo) is seriously good, my new love is ketchup mixed with the chili sauce.
I first tried this as a dip for fries in Banlung, Cambodia, and I've been mixing globs of ketchup and the sauce on the side of my plate to accompany all kinds of dishes from noodles to sandwiches to fried rice since.
Sometimes I make it spicy, sometimes the chili is just a hint but the combo's sassy sweet-hot-acid taste is always a nice addition.
Try it yourself. Always practice safe condiments and don't double dip if you are sharing.