Mayonnaise was another thing my friend's family varied on from mine. My family used plain Kraft or other brands of mayonnaise. They used Miracle Whip. There are some things I like the Miracle Whip better on, like hot dogs or a turkey sandwich, but for tuna salad, I prefer regular mayo.
One time I was going to make a broccoli casserole a lady at work had brought for one of our office parties. It had tasted so good, I got the recipe from her so I could make it myself. While I was making it, I discovered I didn't have enough mayonnaise. I was too lazy to go to a regular store so I went to the nearest convenience store. All they had was Miracle Whip so I thought, ok, close enough. BIG MISTAKE. That was the nastiest casserole I ever ate. I ended up throwing the whole thing out after trying a bite and I know now not to exchange Miracle Whip for mayonnaise in recipes.