Each sprint is unique

Sometimes it is very difficult to control emotions when you see that your team is not performing well during the sprint.
As most managers do, your first assumption might be that guys are not doing their best and not willing to reach the goals of the sprint.
But this is wrong approach for agile manager, forget about your assumptions and stereotypes, just start asking questions.
Answers might surprise you and it will of course change the way you see things. Answers holiday mood, faced some unpredicted technical issues and etc.

So, don’t forget - each sprint is unique! You need to highlight this during retrospectives and keep in mind during planning!
And one more thing - fight your stereotypes.