I think that there are food items that people all like, but they don't necessarily like it the same way. Some like it prepared a certain way and they may not eat the food items if they aren't prepared a certain way. I'm going to list a few items today that I find fit that bill...
I think all egg-eaters would agree that they mostly only like eggs if they are prepared the way they prefer. Some won't eat eggs without salsa, ketchup, pepper, or other sides. There are a million ways to prepare eggs and so the battle is endless with them
2) KD/Kraft Dinner, or for my American friends, Mac and Cheese.
Here is a basic Canadian staple that you would normally only ever eat your own way. There is no bigger lunch bag letdown than if someone makes you a big plate of KD and it isn't the way you like it. Again, there are people who make it with cream, milk, extra cheese, or eat it with or without Ketchup, Bread, or the beverage of their choice to make it go down nicely. People get very picky about this very basic meal...
There will always be an on going battle between the medium rare lovers and the well done people. The ketchup users, bbq'er, and the steak oblivious. It's funny to watch people's reaction about steak, and how they like it prepared and then watch the battle ensue from these 2 sides.
4) French Fries
Again, gravy lovers, poutine, ketchup, salt, vinegar, well done ect. This one is self-explanatory..
Topping nightmare of choices that overlap French Fries by 2 to 1. You could even go into detail about the bun, cheese, and all the fixins. But I would love to see someone who loves hamburgers just to eat the burger and the bun with nothing else. Now that would be funny.
I recall growing up when absolutely EVERYBODY ate white bread. Only the really dorky parents make their kids eat brown bread and we all felt sorry for the little suckers. Now, it's almost exactly the opposite. In fact, I think there could be people out there calling Child Services for parents allowing their kids to eat white bread now...
7) Coffee or Tea
This should be the one thing that everyone would not like unless it is done to their liking. In travelling a fair bit, I have noticed how quirky and miserable I get when I can't get the colour and taste of my coffee exactly the way I like it. It really starts my day off on a bad foot, and I think everyone can agree that there is nothing better than that perfect cup of tea or coffee when you first wake up.
8) Soft Drinks
Try offering a person who only drinks Diet soft drinks a calorie laden, non-diet drink. Conversely, offer a Coke drinker a Pepsi Product, or vice versa. This goes so much deeper too. I love it in the restaurants when you order "a Coke" and the wait staff counters with the line, "Is Pepsi ok?" -Like Pepsi is so awful that you have to ask them this way... This battle has been going on for decades...
9) Sugar vs Aspartame
Sugar has really taken a hit as being public enemy #1 of empty calories these days. Cooks will now substitute it as an ingredient and people very often want a sugar free option. This goes in gum, drinks, and meals. The once proud sugar industry which had us all my the hip is now noticing they are losing their market share rapidly.
Try getting a skim milk drinker to indulge in Homo milk, 2% or 1%. It just WILL NOT HAPPEN. I think most people in the grocery stores when they go to buy milk, just grab the bag of milk that they always have been drinking without ever thinking about it. It's just automatic to them. Getting someone to change the type of milk that they drink would be a very difficult task indeed.
I know that there are many, many more items here, so feel free to chime in and add your favourite, or one that you felt I have missed.
I think it is very comical about how particular we are when it comes to our food-isms, and how we have grown to get there. They have happened over time, and the older we get, the more set in our ways we get about being adamant on the way our favourites are prepared.