Develop a strong attachment to your good looks – as opposed to merely enjoying them while they last – and you will suffer when they fade, as they inevitably will; develop a strong attachment to your luxurious lifestyle, and your life may become an unhappy, fearful struggle to keep things that way.

Each time you kiss your child goodnight, he contends, you should specifically consider the possibility that she might die tomorrow. This is jarring advice that might strike any parent as horrifying, but Epictetus is adamant: the practice will make you love her all the more, while simultaneously reducing the shock should that awful eventuality ever come to pass.

I don't think the feeling of anxiety ever completely goes away; we're even limited, apparently, in our capacity to embrace our limitations. But I'm aware of no other time management technique that's half as effective as just facing the way things truly are.

Pilots were not excused all these rigorous new checks, and when Woodie Menear's turn came, the security screener expressed concern about the presence of a pair of tweezers in his cabin baggage. As it happened, tweezers – unlike corkscrews or metal scissors, for example – were not on the list of forbidden items; Menear was not breaching regulations by trying to bring them on board. But the official paused just long enough to spark frustration on the part of the pilot, who, like his colleagues, had been growing ever more exasperated by each new restriction. This time it was too much. Menear did not explode in rage; he merely asked a sarcastic question. But it was one that would lead to his immediate arrest, a night in jail, his suspension by US Airways, and months of legal wranglings before he was finally acquitted of 'making terroristic threats' and permitted to return to his job. 'Why are you worried about tweezers,' Menear asked, 'when I could crash the plane?

It can be alarming to realize just how much of life gets shaped by what we're actively trying to avoid. We talk about 'not getting around to things' as if it were merely a failure of organization, or of will. But often the truth is that we invest plenty of energy in making sure we never get around to them. It's an old story: some task, or some entire domain of life, makes you anxious whenever you think about it, so you just don't go there.

The good procrastinator accepts the fact that she can't get everything done, then decides as wisely as possible what tasks to focus on and what to neglect. By contrast, the bad procrastinator finds himself paralysed precisely because he can't bear the thought of confronting his limitations

It's quite sufficient a challenge to seek to follow what the philosopher Iddo Landau calls the 'reverse golden rule' – that is, not treating yourself in punishing and poisonous ways in which you'd never dream of treating someone else. Can you imagine berating a friend in the manner that many of us deem it acceptable to screech internally at ourselves, all day long? Adam Phillips is exactly right: were you to meet such a person at a party, they'd immediately strike you as obviously unbalanced. You might try to get them to leave, and possibly also seek help. It might occur to you that they must be damaged – that in Phillips's words 'something terrible' must have happened to them – for them to think it appropriate to act that way.

The advice of etiquette experts on dealing with unwanted invitations, or overly demanding requests for favours, has always been the same: just say no. That may have been a useless mantra in the war on drugs, but in the war on relatives who want to stay for a fortnight, or colleagues trying to get you to do their work for them, the manners guru Emily Post's formulation – 'I'm afraid that won't be possible' – remains the gold standard. Excuses merely invite negotiation. The comic retort has its place (Peter Cook: 'Oh dear, I find I'm watching television that night'), and I'm fond of the tautological non-explanation ('I can't, because I'm unable to'). But these are variations on a theme. The best way to say no is to say no. Then shut up.