But one could also argue that Strombergsson likes football and that he doesn't want to be the one spoiling the match with an attitude. Players can do that themselves. So he is careful with his cards, likes to use the advantage rule and falls for a lot of trickery. His assistants weren't very accurate, one of them had trouble following the last player.
In the second half Strombergsson had to book a few players and show a severe face. It didn't work for me, and perhaps also not for the Sampdorians who, mediocre players as they are, gradually lost their cool and started fouling a lot. Clearly Strombergsson grew a dislike of the Sampdoria players.
In fact PSV has a couple of mediocre players too. Players who, when they receive the ball, need seconds to think what to do with it. They wait too long and lose the ball. Still, notwithstanding the mediocrity, this match it was a bit of a thriller.