Oh yeah, during one quest I was sneaking up on a necromancer to stealth kill with a dagger. Then Lydia decided she didn't like to wait and watch me creep so she decided to run in and get in front of me just as I was attacking. Needless to say I slit her throat instead of the necromancer's.
Lengyel, magyar ket jo barat, egyutt harcol, s issza borat. -- Hungarians FTW! XBL/PSN gamertag: Poganin