Me: I can’t use this material, it’s expired.
Coworker: Not necessarily…
Me: It’s clearly passed the date, I’m going to throw it out.
Coworker: It’s clearly unused, so it’s probably better than something that’s newer.
Me: Ok, that statement is so dumb, I’m going to ask you to repeat it in 30 seconds.  If you can with a straight face, I’ll use it.
*30 seconds later*
Coworker: Can’t do it.
Me: Good.