Did you imagine him still being friendly to you and acting as a subordinate?
Did you think he'd turn hostile and would have to be eliminated?
I imagined that Yes Man was still finding his identity, and that my character would try to sit down, have a serious talk with him, and offer him a partnership in ruling New Vegas. He does seem like a nice guy, and eliminating him seems like it could be difficult considering the massive Securitron Mk2 army.
Also was anyone else incredibly paranoid that he was going to betray you at any moment after you installed him in Mr. House's computers? It was such a great moment, as soon as his smiling face flickered onto the big screen I was like "oh god what have I done".