I did a piece on the Brady Bunch were-they-or-weren't-they-lesbians story, and it left me with two random thoughts about a show that I didn't really like that much, even as a kid, but which I respect in a weird way.
1. I'm increasingly convinced that the secret of Sherwood Schwartz's success is his ability to create shows that are, quite literally, timeless -- they don't exist in any particular time or era. Gilligan's Island is the ultimate timeless show: the jokes were considered dumb at the time and they're dumb now, but they're timeless jokes (hitting someone on the head with a coconut will always be a laugh-getter), the character types could come from any era at all. If it weren't for the occasional '60s reference you'd never be certain when it was made. The Brady Bunch is dated by the clothes and hairstyles, but otherwise it exists in a hermetic, generic world that could represent an idealized version of family life at just about any time. And all the jokes are, if fairly lame, also fairly durable.
Most show have a way of getting stuck in their own time; you watch Friends and hear a joke and immediately know, just by the way the joke is constructed and delivered, that it's from the '90s. And even shows that don't try to be timely wind up incorporating all sorts of then-current cultural trends and fears. The evil genius of Sherwood Schwartz is that he managed to create shows that are eternally irrelevant, and therefore eternally relevant.
2. I'm not the first person to notice that Eve Plumb stumbles over her line before the famous "Marcia, Marcia, Marcia" line ("All I hear at school all day long is how m... great Marcia is"). I'm always kind of glad when things like that get left in. Today, even shows that pride themselves on being semi-improvisational will not use takes where somebody is on the verge of forgetting or missing a line, but I think that as long as the actor recovers and doesn't make a full-fledged mistake, those little moments of hesitation can make a scene work better.