I generally always use the "don't get complacent" team talks when we're winning by 2 goals or less (both half and full-time) and almost never use the "delighted" talk for the whole team (unless we won against much bigger club) and be disappointed with draws even when we're huge underdog. It might have little to no effect (or even a couple of demotivated players) if you're a new manager but as time goes by almost everyone seem to react positively to it. Now most of my players never get complacent/uninterested even when we're the favorite unless it's a second leg cup match when we're leading by large margin. Sub or not.
Also using the "delighted" talk for exceptional individuals after the match will make them "motivated and inspired". Not sure what that means _exactly_ but it can only be good.
Most of my players have professional or fairly professional personality with more than 10 determination tho. None of them have noticeable bad personality like unambitious/casual/slack.