I was taught to serve is not about "me", as a submissive or slave. This is not about me and the best way to remove any personal thoughts, "I need, I want, I see, I thought", you remove the "I".
Physically I was taught to walk behind the Trainer, except to open doors or ensure His seat is clean or...and here, instead of physically walking behind, this is the mental aspect of walking behind.

I could be wrong.