Last night I had to put up with about ten students of varying degrees of drunkenness tonelessly "singing" a bunch of songs from the Silver Age Broadway-influenced era of Disney films. Probably the part of that which really epitomises the whole "fun to think back on, but not so great to actually endure" side of it is when all ten of them bellow the *spoken* parts of the songs.
Incidentally, I'm not so straight-laced that I can't enjoy a bit of mirth and music. But while I love Singin' In The Rain, The Bandwagon, and the style of songs from the 1940s which often appear in musicals from around that time, I'd never say I'm a "fan of musicals" because for most people that means being a fan of Les Miserables, Evita... um... you get the idea.
One of the things I brought up to the other people who were less than enthralled by this little music-fest (or rather, to anyone who I thought was likely to listen) was that many of the words from the Lion King songs make no sense in the context of the film. Simba sings about "the spotlight" and Scar makes a metaphorical remark about "the lights are not all on upstairs" (referring to the Hyenas' stupidity). It extends beyond the songs, too: Zazu says that Scar would make a "charming throw-rug". But the characters in the film should have no knowledge of electric lights, or furniture, or anything like that. There's no technology in their world. I know, they should have no knowledge of the English language either, but we can accept that as part of the internal logic of the film. Just like, if they actually *had* electric lights and so on, we could accept that as part of the film's internal logic, but not if they *don't* have any but still talk and sing about them.
(Incidentally, when I mentioned to one person about there being "internal inconsistencies", he pointed out that some of the animals, e.g. the antelopes, don't speak. That's an entirely different issue, and one I expect to write about in the near future.)
I guess anachronistic references in Disney films can be traced back to The Sword in the Stone, where there was a clearly established mediaeval setting, but where Merlin was able to reference things from the future -- always to the confusion of other characters -- because of his magic powers. This was taken to it natural conclusion (?) with the Genie in Aladdin. But then with The Lion King it just seemed to become "comic characters can know everything."
There should be a page for this on "TV Tropes", which deals with other media besides TV -- in fact there probably already is one, I just don't know what to look for. Basically, I'm meaning where a film establishes a world with its own internal rules, and then one character breaks these rules by making a joke about something no-one in that world should know about. This sort of thing doesn't always matter, of course. No-one cares about anachronistic jokes in Monty Python and the Holy Grail because the film doesn't try to pretend its world has any sort of rules about what its characters are or aren't familiar with. Shrek's kind of a grey area. I don't think Donkey should know what an in-flight movie is, because there are no planes in their world, but it doesn't feel like quite such a big deal somehow.