Why is the woman nervous?

W I’m really nervous. I’m supposed to get my employee evaluation today.
M I wouldn’t worry about it if I were you. You’re a hard worker, you’ll be fine.
W Yeah, but I was late twice last month. The construction around my house really blocks traffic. I have to leave 30 minutes earlier than usual.
M Well, you’ll be measured on your overall performance. Being 2 days late isn’t a big deal, especially since your department has been doing really well lately.