If it's a fine dining establishment, I wouldn't dream of asking for modifications (outside of allergens or religious restrictions). The chef has carefully constructed a specific experience, and I'm going to that restaurant because that chef is good at their job.

If I'm getting a burger or a salad at a mid-level casual restaurant, I'm definitely asking to leave out the ingredients that I don't like.

If Joann is feeding me for free, again, I'm not making any special requests unless I have allergies or religious restrictions. If I know I don't like Joann's cooking, then I am "unfortunately otherwise engaged" when she invites me for lunch ... or I simply skip her contribution at the family potluck.