Do you put mayo in your broccoli casserole?

I've made cold broccoli casserole with mayo in it. Have never made a hot casserole version. What do you mean by underwhelming, taste or texture? Did you use any other kind of cream or egg in it? W/out knowing your recipe, the mayo could be the "egg" which binds the other ingredients together. Or it could be the liquid to add moisture to the casserole. If you don't want mayo, you can use milk, cream, an actual egg, egg substitute.