DH was super fussy when I met him.
He did not eat fish or shellfish, salad or cucumber, spinach, leek, cheese and mushrooms. He could not cook either so lived of take aways, pot noodles and microwave burgers.
I don't remember how it all changed ( other than me laughing at him and his pathetic ways) but he eats everything now.
I don 't mind caterinf for, or eating with vegans, coeliacs etc. but I do find people with faddy diets boring a difficult to cater for.
My book club came for dinner: one vegetarian, one person who has decided wheat and sugar are the devil, one person who has cut out all dairy ( to stay slim) ... It was hard to come up with a meal!
Basically, most food fussiness is bad manners, if not suppressed when eating at friends' houses. Personally I hate blue cheese , game and big enormous English puddings. But I eat it with good grace if someone has been kind enough to cook it for me.