As far as Grover is concerned, I see a lot of complaints in recent years about how much he's been Flanderized, and I . . . kind of have to agree with that, to a certain extent. No, Grover was never the brightest star in the sky, but it does seem like he's just gotten progressively dumber over the years - not unlike, say, Ed from ED, EDD N EDDY, or Kel from KENAN & KEL. Back in the day, I would say Grover was simply just a lot more gullible and a tad absent-minded (or even literal-minded in some cases, particularly with Mr. Johnson); modern Grover feels like he's pretty much de-evolved into a brainless joke/gag character who can't do or get anything right.