People are not good at remembering that we had those same conversations last time and the time before - they get a gut feeling that 'this is the big one', and they pull their money out of the market during the recession and put it back in after everything's ok, essentially tossing a major fraction of their life savings overboard.
What people seem to never consider is that when we actually move out of an expansionist economy, the effects will be much broader than "our stock returns are not so good anymore"; their inability to retire at 65 would be the least of their concerns.