When you try to become over smart with Apple.
Client :- Ask for all user information in registration screen.
Me :- But Apple rejects app if you ask for personal information you don't need. We shouldn't ask it since Apple will reject the application
Client :- "I am more strict than Apple", just do it.
Me :- But...
Client :- Do it!

Developed the app, uploaded on Apple Store for review and the app got REJECTED!!

Reason for rejection :- Don't ask for personal information you don't need !!!

Me :- (Evil laughs)

It's been more than 15 days now, the app is still under review due to multiple other violations already informed by me.

Moral :- Listen to developers, they have more experience than you or DO THE F*****G RESEARCH !!

True story !!!!

Client :- The app is slow on my device, please fix.
Developer :- Working fine on all the devices I tested, are you sure?
Client :- Yes, it's very slow. I can't accept this app.
Developer :- (Recompiles the same codebase again) Here, try this, optimized a lot of calls, took me entire day to do so.
Client :- Yes, it is working fast now
Developer :- (evil laughs)