That got me thinking about the weirder aspects of the game's culture, in which a single day and a raid lockout divides an alleged nightmare (Raid Finder on Mondays) from a safe bet (Raid Finder on Tuesdays). The usual story is that people run their better-geared mains through Raid Finder soon after the weekly lockout finishes, but come Sunday and Monday they're running their less-geared alts, and usually on classes with which they're less familiar. There's got to be more to it than this, but it's a narrative that most players are probably aware of by now.
Out of morbid curiosity, I've occasionally taken my main or alt shaman through Sunday and Monday LFRs but can't say I've noticed a massive difference. There are definitely more times late in the week where I've zoned into a squabbling raid with a two-stack of Determination, but most runs are fairly uneventful. However, one player's experiences are rarely representative, and your own gear and experience play a role as well. A well-geared toon, especially if it's a tank or healer, is at least marginally more likely to contribute a successful raid, and vice versa.
I'm tempted to do a series of LFRs and measure overall raid DPS and number of deaths by day. I'm genuinely curious whether the conventional wisdom is right, and late-week Raid Finders are more likely to encounter trouble than their early-week counterparts.