I had a Nephew who cooked a great shrimp gumbo. After I learned the ingredients, it should have been good.
It must have cost a fortune to make.
Only unusual spice in it that I don't always have in my cabinet is bayleaf. Otherwise, it uses stuff like garlic, oregano, and Texas Pete. It's really forgiving, don't have fresh garlic? put in a little more garlic powder. Like onions? Put in more onions. More people show up than what you planned? Throw in some more rice and another cup of water.
Cajun cooking is like that. My experience is that if you use the recipe exactly, you're doing it wrong. :-)
The key to a good gumbo is the small loan you have to take out to make it.