“对不起”似乎是最难说出口的词，艾尔顿·约翰20世纪70年代发行过的同名热单(Sorry Seems to be the Hardest Word)就是这么唱的。不过，并不是每一位公众人物都觉得这个颇有分量的词难以启齿。
Sorry seems to be the hardest word. So sang Elton John on one of his biggest 1970s hits - but not every public figure seems to find it so tough to utter that powerful five-letter word.
In recent months a broad spectrum of public figures, from politicians, to Hollywood actors and YouTube stars have all publicly expressed remorse.
But with so much remorse on the airwaves, just how can we differentiate a forced apology from a heartfelt expression of remorse?
In its purest form, saying sorry should be an "act of contrition, a realisation that something you have said or done has hurt someone and you want to make amends", says psychologist Geraldine Joaquim.
Made early, a well-crafted apology can be hugely beneficial and can "diffuse the situation and takes the wind out of an accuser's sails", she says.
A need to say sorry can arise in someone's public life and equally at home with their family and friends but, whatever the environment, how well it is received depends on how personalised it feels.
Experts say the formula for an affective apology can be summed up with the acronym CAR:
"People want the response to be personal to them, to feel that they're being listened to and taken seriously," says Martin Stone, of PR agency Tank.
He says that, in the professional sphere, the phrase "formal apology" is often used, but, in reality, the opposite is what is required.
From businesses, governments and organisations, a scripted response will fail to resonate as it will not convey empathy and compassion.
Whether online or in person, the timing and choice of language in an apology are decisive factors.
"Firstly, it is important to show that you understand and sympathise," says Stone.
"It is vital that any business or individual making an apology understands the focus - is it sorry for the way it's acted or is it sorry that the complainant feels the way they do?"
Spontaneity - watch out for the speed of response, the quicker the apology comes, the better indication that the person making it has felt an immediate sense of guilt
Body language - if genuine, the person making the apology will be looking for listening clues to see if they are being understood, such as eye contact and facial expressions
Vulnerability - performed apologies always have a sense of being "acted out", and are often accompanied by too many theatrical gestures. If the person is genuine they will provide "humbling signals"', such as a lowered head, to indicate remorse and vulnerability
Denial gestures - the biggest clues of insincerity can come after the gesture itself, with non-verbal signals that silently reject the words used; this can include looking to the floor and smirking.
Linguistically it is also important to avoid dehumanising statements or promises that can't be kept.
"Don't say that you'll ensure that this will not happen again if you're not confident it won't. It could come back to bite you," Stone explains.
Equally, the use of "but" can hugely change the tone of an apology.
As Stone points out: "I'm sorry but…' sounds like you are making excuses and aren't actually taking any form of responsibility.
"It may be three letters but it can instantly make an apology seem hollow."