Jack nodded a little bit. "Yeah. I mean, if I couldn't remember, I wouldn't be much use, now would I?" He chuckled softly. "But yeah, that's why time traveling is so…hard on the travelers, sometimes. Because we spend weeks or even months in a time period, and then we come back and everyone we know hasn't even aged a day. It's hard on our loved ones, too, because…" He shook his head. "I've seen things on these trips that…make it hard to sleep sometimes. And it's hard on other people, because to them it seems I change radically in just ten minutes, even if for me I've been gone for months."