I've found similar things on mine, my squad is very young though so i imagine the 'pressure off' teamtalk fits with them quite well, i remember on an older FM i had a very professional squad at Wolves so if we were favourites, usually were, i told them i expected the win and they usually got it.
I've tried a few different team talks, expecting a win, want to be impressed, etc. and they only ever get a couple of players motivated or happy opposed to pretty much the whole team when i tell them to relax, perhaps it's the small club mentality? Always being the underdog.
I've nearly slipped up a few times on lower clubs lately though, my defence seems to go to shit when i play them, i'll get an early lead and then they equalise pretty quickly before shutting up shop and frustrating the crap out of me until i go 'overload' at the end to force a result.