What's that supposed to mean? • Sam/Dean (9x10)

"Come on man, can't you see, I'm poison. People get close to me they get killed, or worse. I tell myself I help more people than I hurt and I tell myself that I'm doing it all for the right reasons and I believe that. But I can't -- I won't drag anyone anybody into the muck with me - not anymore." "Go. I'm not going to stop you. But don't go thinking that's the problem because it's not." "What's that supposed to mean?" "Just go."