Within my own household, I grew up with my dad making macaroni salad with Miracle Whip. Along with celery, onion, some spices and occasionally tuna (which I hated) and eggs.

My wife grew up with mac salad with mayonnaise, onion, celery, tuna and spices.

So we have my sister and her husband and 2 mutual friends coming over tomorrow. We're making 2 batches of mac salad. I check with my sister to see if she still prefers Miracle Whip version, and how about her husband and the other 2. They all like mayo. No problem, we split the batch 1/4 one way, 3/4 the other.

Then it gets complicated.

My wife and daughter want tuna in it. 5 others DON'T want tuna, 1 will tolerate it.
Brother in Law is allergic to eggs. No big deal, neither version was getting eggs.
One mutual friend is VERY allergic to celery.
The other mutual friend is allergic to raw onions.

Screw it, we're not making 6 different batches....or however many permutations that turns out to be. We'll just warn you on what's in it.