"Better I say it before someone else does"

Part of the commentary's appeal is that it feels like armour. If you've already told yourself that the presentation was poor, nobody else's verdict can ambush you. If you expect to be found out, you won't be humiliated when it happens. Getting your criticism in first seems like a sensible precaution.

I think this goes back to where the habit began. A child who's often criticised learns to scan herself for faults before anyone else can find them. It's a kind of early warning system, and in a critical household it may well have worked.

Look at how it performs now, though. Start with how often the blow you're bracing for arrives. In the meeting, you gave a wrong figure and braced for judgement. None came. Your colleague corrected it pleasantly and everyone moved on. Nobody else was holding the opinion the commentary delivered to you as general knowledge. If you think back over the last month, you'll probably find the same pattern. You've delivered dozens of harsh verdicts on yourself in advance of criticism from others that never came. Other people are mostly occupied with their own performance and their own commentary. You've been defending yourself against an attack that almost never comes, and the defence itself does you harm.

Then consider the rare occasions when criticism does come. If the armour theory were right, you'd take it better for having got in first. My guess is that you take it worse. A person who's spent the morning telling herself she's useless hears her manager's mild comment about the report as confirmation of everything. Someone whose view of herself is steadier can hear the same comment as information about the report. The commentary has already worn you down by the time the criticism arrives, so it lands harder.

There's also a cost in how you come across. People who expect to be judged often behave in ways that invite it. They apologise before they've said anything and run their own work down as they hand it over. They deflect praise with a list of what was wrong. Colleagues tend to take people at their own valuation, at least at first. If you introduce your report as "probably rubbish", some of your readers will start reading it that way.

You can't prevent other people from criticising you sometimes. It's part of doing anything. The best preparation for it is a fair and steady view of your own work, one that can take a criticism on board without collapsing.