Figure out possible reasons why a cat gets fussy

We know that cats are independent creatures who only tolerate us humans. But what makes them fussy. And what does 'nervous' mean. The dictionary definition is "too busy with trifles" anxious or particular about ridiculous. " (See: The Macquarie Dictionary.) But when it comes to cats, my definition of "critical" has more to do with like or dislike of different types
Some cats are very careful about what they eat. They prefer a certain brand of food, and failing that, the first hungry than eat something they are not sure. Yet they will deign to "novel food" if nobody sees food. I think they just do not want us to see them 'true'.
Other cats can be picky about where they sleep. And if it smells funny, because you just washed the bed, they talk about their displeasure, and continue to "make their own 'back, go to bed, their backs to add flavor. And if you bed in another room for one reason or another, be prepared for your cat to refuse to sleep until it is returned to its rightful place.
I know cats to stop using the litter box because the type of litter is changed. It feels and smells different, so they are not sure they will like it.
What all this means that cats are creatures of habit. They do not change unless they are the ones who do. Some cats like to sleep on a favorite chair for years, rather than go to sleep on the bed. Nothing would entice them back to the chair - they are not interested. But if you chair or recovered, then you're the one "wrong".
If you decided to change the cat food, do it slowly over at least one week. Start by adding a bit of the new cat food the old type, and select the new, while there is less of the old, so your cat can adjust to the new taste. The same applies to changing litter in the litter box. Do it slowly over a period of at least one week. If you wash the cat bed, do something, but leave what is still "smell right".
I have many websites and forums that will tell you to just let the cat down ten minutes, and if not eaten, take him away. This may be a way to retrain your cat not to be nervous when you eat, but you will be that one way to your cat? I prefer my cat to be able to choose what she does and when. She eats "cloud" or "sauce" from the letter "casserole" type cat, but then comes back later to the rest. I would not want her to have to eat quickly or lose. But it's my choice.
Yes, cats can be picky about what they will do and when. But for me it is a part of the joy of having a cat. They are independent beings and their idiosyncrasies are part of what makes them so adorable.