The chief executive also said he has been saddened by the impact of a few bad bankers on the reputation of the whole industry.
“I find some of the behaviour that has been exposed sad and aggravating because the vast majority of bank staff are honest people who work hard to serve their customers,” he told customer magazine RBS Business Agenda.
“Likewise, the vast majority of things that banks do are done relatively well and competently.”
But he also said it would take time to root out the culture behind this bad behaviour.
“Culture changes over a generation, not on the turn of a sixpence,” he explained.
Last week Hester said the bank was coming close to being able to pay dividends again – a key step in preparing the bailed out bank for a sale back to the private sector.