So much of this game comes down to confidence and having a mental edge over your opponent. In the first period today, Olofsson went for a puck at the boards along with a Montreal defender. Olofsson could have braced to the point side and worked down low, or braced to the corner and tried to turn up high. The defender had to pick one of those options and be prepared to defend it. Olofsson is skilled enough to make either play, neither gave an inherent advantage. Olofsson beat him and he backed off very quickly, giving Victor time to set the power play back up.
The Sabres have spent a decade losing 65% of those scenarios. Having low skill can limit you in situations like these and make you more predictable, but a lot of it is ~vibes~ and having a feel for the ice that unlocks with high confidence and is impossible to grasp otherwise.
Boston's players are skilled but they aren't more skilled than plenty of teams, maybe even some mediocre teams. But part of the "chemistry" that makes them so good is confidence instilled by the presence of something older than plenty of their players' tenures with the team. They never blink first, they dictate how a battle will go before it even begins
The Sabres threw this away and haven't fully recovered it yet. The talent is becoming tantalizing enough that if they get it back they will dominate the league, but I'm not really sure how they can complete this step