I can't stand the white gloppy mayonnaise-y mess that most places call macaroni salad. It wasn't till last year, that I discovered a deli (St Mark's Market) that sold a version that I found edible. Their main flavor was mustard, with very little mayo, but it contained almost nothing other than noodles and a few carrot strips. I went home and tried to recreate the seasoning. Over time I added to it and made it a little more substantial. I also found that dill really helps prevent the taste from being too flat and balances out the mustard.
1/2 cup cooked macaroni
1 hard boiled egg
1 celery stalk
1 Tbsp fresh dill
1 tsp grainy dijon mustard
1 1/2 Tbsp mayo
Salt/Pepper to taste
-Cook your macaroni and boil your egg in advance and let cool. You might want to add a touch of olive oil to the pasta so it won't stick together
-Chop all veggies and herbs. Cut up hard boiled egg
-Combine everything and chill, or serve right away
This recipe works perfectly for potato salad too!