'A Jack of all trades, but a master of none'
Everyone's probably heard that saying.
It's not the whole saying... there's another line.
'But better than a master of one'
Those old sayings you've heard have been twisted to mean the opposite, either by religions or capitalism.
'Blood is thicker than water'
Nope
'The blood of the covenant is thicker than the water of the womb'
Which means that the family you choose, is better than the one forced upon you by birth.
There are loads more.
Just a bad apple, say the police when one of them commits a crime, usually an act of brutality.
The adage is “One bad apple SPOILS THE BARREL”. #ACAB

@Anomnomnomaly @piebob " The customer is always right"
"In matters of style"
Not quite the same meaning :)