I'm not an event fan (or perhaps more specifically, not an MSM fan, especially Endless MSM), but I also don't think of the three things you cite (Meme Monday, Fun Fact Friday and the cowboy hats) as events so much as just regular parts of SN (in much the same way that the Weekend Book Recommendations post is, or the daily Music Salon or the Stacker Saloon). Yes, there's sats at stake for the first two, but for the most part, it's something specifically there are a form of entertainment (at least to me), and helps build the culture of the place.

That said, one-day events have the advantage of being short enough to avoid without completely dropping out of SN, so they don't bother me, per se, even if I (or a large number of folks) might not find them interesting or entertaining.