Dobby infuriated the Malfoys, it wasn't that he ever did anything really wrong but rather that they seemed to resent him existing in the same room as then.
"A good house elf shouldn't be seen OR heard!"
Lucius Malfoy would snap at him everytime their paths crossed. This would always be followed by a sharp kick and a punishment for any perceived problem. "By the way, I found a crease in my bed sheet this morning you useless cretin!"
"Dobby is a bad elf. Dobby has let down his master". Dobby promptly began banging his head violently against the marble fireplace. "Bad Dobby! Bad Dobby!"
Lucius didn't look the least perturbed at this sudden outburst. On the contrary, he strolled from the room calling over his shoulder, "don't damage that it's worth more than your life. Try the floor!"
The next time Lucius came across Dobby it was in one of the bathrooms as the house elf was vigorously scrubbing the bathtub. "For Merlin's sake! Next time you get in my way, I'll transfigure you into a mouse and squish you!"
"Dobby is sorry Sir. Dobby is not meaning to be in your way".
"Then get out now! And have you punished yourself for disturbing Draco earlier yet?"
The incident he referred to was when Dobby had meekly knocked on the door to Draco's room,
"Mr Malfoy are you in there? Can Dobby make your bed please Sir?"
He had waited patiently and upon hearing nothing slowly opened the door. There on the other side sat Draco staring at the door expectantly. Dobby suspected he had purposely remained quiet so he could scold Dobby but promptly realised this was thinking bad of his owner, he slapped himself hard.
And thus was the life of Dobby the house elf, and this is how it would probably have remained forever if it wasn't for a conversation he overheard May 1992.
Dobby was sweeping outside the sitting room when he overheard whispers. He didn't know who Master Lucius was talking to as he hadn't seen anyone coming in.
"This year. Yes. It will be opened."
The other man replied but too quietly for Dobby to hear. He considered listening for a second but shuddered at the thought.
"Bad Dobby! Dobby shouldn't listen in on master's private talks!" He hit himself in the stomach hard and doubled over.
"50 years it's been but the chamber will be opened and that school cleansed of mudbloods. First them and then it'll be blood traitors like that filthy Weasley family and yes hopefully the famous Potter boy too" Lucius spat angrily.
Potter? Surely master didn't mean Harry Potter? The boy who's defeat of the Dark Lord had led to so many good things including the improvement of treatment for elves? Dobby was paralysed to the spot. What should he do?
He agonised over it for hours that day while he cleaned the huge Manor from top to bottom.
"Elf! We're going to dinner with the Goyle's. While I'm gone, degnome the garden, pull up all the weed, clean all the bedsheets, and prepare our supper." He grinned nastily, "We'll be back in two hours. I'm sure that's plenty of time for you to do all that".
The Malfoys left laughing and it was at that moment Dobby made a decision. He snapped his fingers and disappeared from the Manor and reappeared in number 4 privet drive.
