Fall allergies and cooler weather.
Truth be told, it's perfect right now - still hot during the day but little humidity, cool in the mornings and evenings. It's been gorgeous.
I just hate, hate, HATE knowing that summer is over.
Also, sometimes I don't like the fact that the little one is back in school. We have to be more diligent with bedtimes and get back into the routine of school and homework, and though she's a smart little cookie, she's not too keen on school.