Mail.app just gave me a fright. I thought I'd broken mail delivery today when I restarted SpamAssassin on the newly installed (ahem, more on that later) gomorrah.
I had no messages dated "Today." only "Yesterday." Fortunately, I quickly realized that was merely because it was now after midnight. It's not "Tomorrow" until I go to bed or the sun comes up, dammit!
Once again, Mail.app makes me pine for Batmail (which had been hacked by someone (I don't remember whom anymore) such that you could make it do the inteligent thing in this case. "If I ask for my mail from 'today' and it's before 4am, include 'yesterday' as well, since my brain is probably not functioning well enough to figure out where all my mail went."). All MUAs are just a pale imitation.
What also disturbs me is that I hadn't noticed this until now. I must be getting old or something.