My "L" used to get really upset once in a while when I would have to drop him off at his mom's after spending the whole weekend with me. He would be really quiet in the car for a few minutes and then say, "This is the part of the weekend I hate the most!". And he meant it, too. He was never close to tears but he wasn't too happy, either. But I used to tell him that the week would go by fast and that we would get together again the next weekend, which we always did. There were a few times when he actually got to spend a surprise extra day because his mom needed to do something and asked me if he could (which I always said yes...). That made him just flip for joy!