When I was 6 years old I had a bologna and mayo sandwich go bad on me. I threw up so hard it shredded my throat.
5 decades later I remember that taste and when it comes up in conversation I want to hurl again.
I am OK with mayo blends in things like potato salad and mac salad.
Put direct mayo on my sandwich and I will just throw it away (I have done so in catered events where they just put mayo without asking anyone).