Ipod nano 1st gen...random freezes

I have a 1st gen. nano and sometimes the nano just acts crazy...like ill be done listening to my music and i go to turn it off...but it wont. Can anyone explain this? I mean...it doesnt actually freezes, because i can still play music. I am not that worried about it anymore because i have decided to buy an ipod touch. But i was wondering if i am doing something wrong?? Because if i am doing something to damage the Ipod i dont want to continue it when i get the ipod touch...please help ...thanks

Does it just sound like a defect??...any ideas...has this happened to anyone else...im not interested in getting it fixed but just preventing it from happenening to my Ipod Touch.