I am a short order cook, and it's really no big deal. The analogy is a poor one, really, because it's not "I'd like hash browns and bacon/ I'd like a hamburger and fries/ I'd like grilled cheese and a salad/ I'd like a stir fry". I've been know to say "Nope, can't do that tonight". But here's how I make things easy:
I tend to make parts to put together as people wish. So, casseroles are out. Last night I made spicy hamburger, quinoa, and cabbage fried up in the spicy hamburger grease. My oldest just had the hamburger, though she will often have quinoa too. My youngest wanted chicken from last night, so I heated that in some chicken broth. DH and I piled the whole lot together with some hot sauce.
My dd2, 7yo, just eats whatever, but dd1 likes a lot of the same foods, so I will often start with her if I'm not sure what I want to make. "Do you want hash browns or mashed potatoes or quinoa with dinner?" What she answers I'll make sure to have that be part of the meal. So, one night the veggie was beets. DD1 chose hash browns. You cannot believe how delicious beets are with hash browns (with blue cheese sprinkles. Mmmmm....)
Other times I'm more organized with meal planning and just make sure everyone has something they like, even if it means pulling out the vanilla yogurt for dd2. Cereal is a totally acceptable option. So is toast. Carrot "fairy wands". Apple slices. There is almost always room on the stove for a hard boiled egg or broccoli.
This all started because of allergies. I was adamant before about not making different meals, but was forced to reconsider, and it hasn't been that bad, in part because of how I organize the meals, and always have easy options for those that would otherwise opt out. The cheese stays on the table as a condiment. I make myself wheat toast when I make a batch of cornbread for the family I can't eat (yes, I have allergies that make me the one looking for something different.)