I hate being a substitute

I bet every one hates being a substitute. We are who we are and we have our own unique value.

I love it when I'm being find by you but not only when you need me for favours.

I love it when you tell me random stuffs but I hate it you only say those things when you're in bad mood after argued with that person.

What am I to you?
Don't make me confuse again and don't turn me into a substitute or your backup lover. I had enough of it.

Thank you in advance.