BTW, my backchatting and sarcasm was adored at age 3, hated age 7. What changed? I will not encourage DS in behaviour I do not want later... even waking at night has never been "fun", just making him go back to sleep. It's too confusing to do otherwise.
I've seen that soooo many times. It sucks hey? This is why I try to be a big picture parent, rather than doing something because it makes me or my child feel good for that moment, I like to make sure what I am doing is going to make us both feel good (or be happy/secure etc) long term.