I've remembered a bit more:

T: Why didn’t you ask for an extra session to replace the one we lost?

Me: I didn’t realise the effect of the missed session until it was too late. Anyway, it would have been an emergency session, and we know from experience that emergency sessions don’t work.

T: Haven’t we learned from that?

Me: Yes! We’ve learned not to try again.

I think T was trying to persuade me to try again in spite of my experience. But that’s not learning, is it? It’s the exact opposite of learning.