These repeat offenders are trying the patience of their most loyal customers
To paraphrase Oscar Wilde - once is misfortune, twice is carelessness.
What words do we use now when it comes to the perennial computer glitch repeat offender, the Ulster Bank?
It's the fifth time since June 2012 that so-called "technical failures" have robbed customers of access to their own money.
Yet again salaries haven't been paid in, benefit payments are missing and direct debits have gone awry.
Some Ulster Bank customers haven't been able to pay bills and have expressed concern about being blacklisted with credit agencies.
The timing of this latest glitch couldn't have been worse - or more ironic - coming as it did a day after Ross McEwan, chief executive officer of Ulster Bank's parent firm Royal Bank of Scotland, told this newspaper he was confident all IT issues had been resolved. Not so, it seems - and customers have now been warned it could be the weekend before their accounts are back to normal.
Of course, other banks have suffered similar woes, but, for some reason, it's Ulster Bank that keeps hitting the headlines.
Problems first emerged three years ago - on June 19, 2012 - when a software update went wrong.
That led to a catastrophic computer meltdown that left millions of Ulster Bank customers unable to withdraw cash or view an up-to-date account balance.
Almost nine months later, there were two other problems: firstly, on March 6, when clients couldn't access their accounts or withdraw money and, then again, on March 28, when they were unable to use mobile banking for hours.
Customers were subjected to even more misery on December 2 that year, after an IT problem meant they couldn't access hole in the wall machines, use cards or access online banking.
Then, last April, computer problems on Easter Monday meant cash machine withdrawals were taken from some accounts twice.
The bank's beleaguered resumé to date was thrown into sharp focus yesterday when customers complained that -yet again - they weren't given any information from Ulster Bank about the problem when it arose.
Could that be a glitch too far for many of their most loyal account holders?