Mr. Bump appears in every single episode of season 1 and every episode but two in season 2.
First TV Appearance of Mr. Rude, Miss Scary and Miss Whoops.
Mr. Tickle and Mr. Grumpy are the two seen with the most characters in the show: 30, including themselves.
Mr. Rude and Mr. Scatterbrain are the only characters to retain their voice actor (Joey D'Auria) in the UK version, presumably because of the former's French accent.
Mr. Jelly and Mr. Fussy were renamed Mr. Nervous and Mr. Persnickety (though changed back to Mr. Fussy in Season 2 per suggestion of Chorion disliking the name, as well as changing to a Dark Green color) respectively in The Mr. Men Show (2008).