Chicken soup (X) is not complete without a generous bunch of fresh dill (Y) thrown in just before serving.
French onion soup is not complete without the crispy cheese bits on the outside of the ramekin.
Oatmeal cookies are not complete without raisins.
Deviled eggs are not complete without a dusting of paprika.
No sandwich is complete without mayonnaise. Lots of mayonnaise. And if it isn’t Duke’s, it isn’t mayonnaise.
Going number 2 is not complete without also going number 1.
Seriously. It just doesn’t feel right to only have a number 2.
Know what I mean?
For me, it’s usually a number 2 sandwich on number 1 bread. You know, the second number 1 that presents itself after number 2?
Not only have I never had that, I’ve never even heard of it.
Apple pie is not complete without vanilla ice cream. And the pie has to be warm!!
Steak is not complete without grilled onions and mushrooms.
Tuna salad is not complete without pickle.
Chicken or egg salad too.
Omplete is not complete without a c.
Wasn’t that a song by The Motels? ‘Take the “c” out of “complete” and it’s “omplete”.’ 
(It scans correctly with the music, too!)
A roast turkey is not complete without paper frills on the leg bones.
Tomato soup is not complete without crackers, a grilled cheese sandwich and an ice-cold glass of milk.
We Will Rock You is not complete without We Are the Champions.
Jerry Maguire is not complete without Dorothy Boyd.
A sock is not complete without a matching sock.
This is the FIRST one I agree with; the rest are all optional. (Well, except for the obvious “two socks,” and going #2 without going #1–we actually had a long debate over whether that was even possible in a previous job I had. Yeah, we really got pretty busy at that company!)
X is not complete without Billy Zoom.
Phyrexians are not compleat without glistening oil.
…And I’m reluctant to google that.