Why is Dobby different from the other elves? Also Ron's grim joke about Dobby..

[vmonte]

No: HPFGUIDX 88050

vmonte wrote:
What is Dobby's story? What makes him so different from the other 
elves?  I understand that there comes a time in history when all 
repressed beings eventually stand up to fight against slavery. But 
why only Dobby? Will this begin to change in the next books?  Will 
more elves become inspired by Dobby?  

Also, Ron tells Harry in one of the books: 'If Dobby doesn't stop 
helping you he is going to end up killing you.' (Not the exact 
wording.)      

Should we take this to mean the Dobby will blunder in the future 
somehow?