Just a couple of days ago I was doing an upgrade from 6.4 to 6.5 and yum died in the middle; fixing that was quite hellish as rpm somehow decided that multiple conflicting versions of several packages were installed at once (eg glibc v131 and v137), and it wouldn't do anything until that was fixed (it wouldn't even attempt to fix the problem until it was fixed... "yum-complete-transaction" just complained about things being inconsistent and wouldn't roll back or forwards - "transaction" my arse). Ended up fiddling with "rpm --no-deps" to fix individual packages after drawing out the dependency graph by hand :(

I've had problems with individual .deb packages before, but never broke the whole package management system quite like that before :P