Tuna salad sandwiches - why are brought ones better than what I make at home?

Do they add MSG or some sort of magic ingredient. But when I make tuna salad sandwiches they’re always so bland compared to when I buy them in the store… Even worse, I like the ones they serve in the hospital…

What am I doing wrong when I make them at home? It’s literally drained canned tuna, mayo and lettuce on buttered bread.