This is actually kinda sad. Crowley just wanted a friend, he was having a good time with Dean. I think that Crowley made Dean into a demon because he thought Dean was super cool and wanted to hang out with him.
And then years later, when Dean's death happens and he's in hell, Sam purposefully messes with the car and plays crappy music so that maybe Dean will come back to haunt him. Anything to see his face again, hear his voice one last time. <--- THIS IS NOT OKAY!! *sobs quietly in corner*