Exception safety in day-to-day life

Most of us have "doh" moments, when something we normally do fine -- locking the door, reading an important letter without putting it down and losing it -- we completely fail to do. What I think is that once something like that is a habit, it will go fine -- unless it's interrupted, which is when mistakes happen. If someone speaks to you just as you're shutting the door, you then go into "I must remember to lock the door" mode. And most of us are much less reliable at "I must remember to do X" than in following an ingrained habit. (Some people are very good at remembering to do one-off tasks without making notes, but probably exhibit the same flaws elsewhere.)

My advice is, form the habit that when interrupted, you commit or roll-back the current task. So, if someone speaks to you when you're shutting the door -- open the door ajar again, and you will probably automatically shut and lock it. Or say "hold on a sec" and lock the door then. Don't wait paused in the middle of the door-locking activity, because you're much more likely to get distracted.

The thing is, locking the door goes fine 364 times out of 365. Which is very good, but to never, ever, get it wrong, you need it to be right every time in 20,000 I think competent, organised people are not those who never experience those little lapses (although that helps), because that only reduces the frequency, but those who ensure that when they do experience them, they recover well, either because (A) they have this habit or (B) they have another back-up, like leaving a key with a neighbour.