The ones that make you look like you've had a full night's sleep when you haven't. The classic is Guerlain Midnight Rescue (which as far as I can tell works by irritating the skin a tiny amount but not too much so you look a bit pink rather than pale green) but also shadows which give the effect of 'a wideawake eye'.
If I haven't had a full night's sleep, the last thing I want is someone thinking I'm bright and perky and expecting a corresponding degree of bright perkiness from me. If I'm feeling like death, I'd rather look like death and then maybe someone will cut me a bit of slack. In fact slightly worse than death would be good because I like managing people's expectations and we can all be pleasantly surprised if I avoid dribbling while I talk.