I sometimes hear conference speakers admit they only finished their slides minutes before their talk started. Or I see them the day before admitting that they still have to write the whole thing.
Whether you’re presenting at a huge national conference or a smaller local group, this is simply disrespectful to the people who take the time to be your audience.
The only reasonable explanation I have for why people do this is that they’re trying to manage expectations. Concerned it won’t go well they make as if it was a last minute job, even if it wasn’t. If it does turn out to be a disaster then, well, they didn’t try hard. If it’s a success, even better! They just threw a great talk together without any effort.
But when a speaker admits this kind of thing, all I hear is that they don’t care enough about my time to prepare and for some inexplicable reason, they’re terribly proud of themselves for it. Bragging about it almost.
Not all talks require major preparation but even the shortest and most basic require proper consideration.
Not everyone has time to prepare in-depth talks but if you know that’ll be a problem for you, perhaps you shouldn’t agree to speak in the first place.
If you do find yourself ill-prepared though, might I suggest that you don’t let your audience in on it.
Don’t be proud about wasting their time.
That just makes it worse.