Selecting object automatically smooths it

whenever i select anything eg cube or cylinder it “shades smooth” same as when we do it through object properties and doesn’t revert even when i “shade flat”.

Please help it is really frustrating.

Did this keep happening for a new file too?
Have you tried to load default settings in preferences?

Yes it happens for the default cube too.

Did you load default settings in preferences?
Maybe mouse/keys are messed up.

Thanks I never thought the problem was in preferences but somehow it got corrected.Although I remember not changing anything in the preferences .Thanks for helping out.