One of my favorite dressings is a mixture of
mayo
ketchup
lemon juice
Yummy - More mayo than ketchup btw.
Hmmm - that reminds me of "goup," a local condiment served at the drive-through-only burger joint that all the youth of my city hung out at / had to visit if you were "cruising town" when I was a teenager. It consisted of mayo, mustard, and pickle bits and we used it to dip our French fries into. You could also put it on your hamburger.
Fond memories.
I still make it as a homemade tartar sauce for breaded fish.