Buffy arrogance is both her greatest strength and weakness
1 her strength when her opponents are playing mind games with her. It gives her the phrase the power on through and block out what they’re saying so she can deliver the final blow on them it also helps not think of the possibility she might die seeing how dangerous her job as the slayer is
2 how is it her weakness Buffy not always thinks things through or who she’s facing when she first meets their by she doesn’t know what that force or enemy is capable of for example her first encounter with the master made her unaware that she was meant to set the master free from being their
Her encounter with the first evil she arrogantly taunted the entity thinking she could handle it but after it departed she felt it’s very infinite power, making her realize she underestimated who she was up against and even did her best to never make that mistake again in season 7 as we know when the first became the new main villain Buffy was always on edge and cautious du to her first encounter
3 was Adam after learning what Maggie was building she tried to face Adam but underestimated his intelligence for example she tried using a taxer blast on him which failed when Riley freind tried to use it on him only to see him feed on it instead
4 glory Buffy first encounter with glory was a huge surprise after her first encounter and when she stood up to the watcher council or arrogance was replaced with fear after she found out that glory wasn’t a demon but a hell god
So in all tends in purpose Buffy arrogance is what gives her the strength to defeat every enemy because as jack sparrow one said but better not knowing what moment may be you last that’s how it’s her greatest strength the same as it’s also her weakness because when she faces her enemy during her first confrontation she doesn’t know what it’s capable of