Because she ain't made for this life. Heavens knows I wish she was." There was a pang in his voice. "Wish she was like my others, content at settlin' down with a husband 'n raisin' little ones. Ain't Kaylee though. All of the others, for them bein' adventurous is movin' three towns over, but she's got a different spirit." He shook his head. "She's like a lil' wolf pup, gotta run around, explore the 'verse, git in a touch of trouble, throw her head back and howl at the moon before she turns into an old dog like me." He let out a wry laugh before sobering. "Can't keep a spirit like that chained to the ground, especially hers and that penchant for ships."
-- Survival (Chapter 16) by TuJiaoZuo