I third that - You say this when you're so into it that you're like the thi

You say this when you're so into it that you're like the third person in a conversation that no one asked to be in.

I third that, and I'm gonna text my grandma about it. This is the best, and you're just wrong.

I third that, and I'm not even tired. This is the best, and I'm gonna prove it.

I third that, and I'm gonna take a picture of it. This is the best, and you're not even close.