They pay hard earned money to watch the professionals do what they're good at.
In that instance, John Stones was doing what he was good at. He didn't mess up, he won the free-kick. The fan reaction (in that circumstance) was stupid, IMO.
If it was Jags, or flappy Funes or chuffing Hibbo doing it yeh, i'd have been worried, but Stones in those situations is composed and knows he has the ability. Let him get on with it. Once it cost us vs Swansea, (and again Howard played an equally as large part in that cock up) he learnt his lesson and didn't do it again.
He's 22. He was 21 at the time.
If he trends like most other defenders, he won't be in his prime for about 6 years. It's scary how good he's gonna be.