My family is a trip. Half the people don't eat half the ingredients, so we literally make them in stages, mark which are which, set them aside, add more ingredients, mark them, set them aside, and so forth.
Our basic ingredients, though, are thus:
Real Mayonnaise (Hellman's is our brand of choice)
Paprika to top them off.
Simplest way, and at the end of the day, we usually have four basic varieties:
1. Mustard with relish, no mayo.
2. Mayo with relish, no mustard.
3. Mustard and mayo, no relish.
4. Mayo only, no mustard or relish.
Of course, then we also have just the plain hard-boiled eggs for people who don't want ANYTHING added.