"You've been working on this for 6 weeks, and I don't see any changes. What have you done?"
"I completely overhauled the backend, now everything makes more sense and we're using more modern APIs"
"But nothing's changed at all! The front-end looks exactly the same!!"
"*sigh* The new backend is also more secure.. "
"Oh, so it's a security upgrade, that's good, but why did it take six weeks?"
-_-

Ooh it hurts but doesn't he understand the basic concept of backend holy shit...

It's really difficult when you have to explain that to make great changes you have to start from the bottom

Holy shit..... Really difficult to explain to a none technical person the concept of a backend. My daily problem

Frontend is the dining room in a restaurant. You order your food and get it.
Backend of the restaurant is the chef, the time taken to cook the meal, the preparation of the ingredients, buying them, WHERE you buy them from, balancing the books, paying the wages of the employees, the communication between kitchen staff to make sure the right meal is cooked for the right table and it's all finished at the same time.....
Improvements to back end make you get the meal faster, means the meat is sourced locally rather than from another country where you don't know what's happened to it, better practices for avoiding allergen contamination are employed, and your waiters practice making their handwriting neater so the chefs can read it more quickly.

Maybe it's too far an analogy and you'd be patronising your boss to explain like this, but a boss that doesn't understand the value of what goes on in his field of responsibilities is gonna suffer for it eventually.