I don't usually bother listening to remixes, but yes, quite a lot of them kill the origina songs painfully. The only ones I like are: 'Dead Is The New Alive- Manipulator Mix' [link] 'In the City- Allen Morgan Mix' (no vid, sorry) 'What Are You Waiting For- Allen Morgan Mix' [link]
I generally do hate Remixes, unless they're legitimate reformulations of songs. Basically, if the remix goes by the genuine sense of the word, it can be fine. Most remixes though, are songs that get reformed and elements of the song are placed elsewhere, and typically a different/additional beat is added, usually to make it dancier. Remixes in their pure form, where the song is simply reorganized in a different manor, can be fine.
I mean I don't hate remixes in general, I mean some can actually be really good. But if a certain remix of a song is shit then I don't like that remix itself.