[Joeboy]

I also have a tendency to say "Last century", thinking it comedically suggests "a long time ago" without it actually being that long ago. But as time goes by it obviously becomes legitimately a long time ago, and I suspect young people wouldn't see the attempted irony at all.

[benj111]

'last century' 'turn of the century' etc just make me think the 1800s. So I just say last millennium.

Probably get confusing again when people start referring to 'the 20s' not as the 1920s.