things i've become accustomed to saying on a regular basis

you're a silly goose.
that's my personal space.
did you get everything out? [in the restroom.]
seat belts!
we don't touch other people's things.
what do we say when we burp/toot? no, what do we say?
let's move! / let's keep moving!
time to ... it's really time to ... right now, it's time to ... actually, it's past time to ...
i know, we'll take care of that later. right now, it's time to ...
are you finished?
it's not a race.
that's called an annoying question. [this is a new one for me, as certain repeated questions are actually wearing on my nerves.]
that's not your job.
good job!
i don't know that song.
i don't know all the words to every song on the radio.
what happened to...? [this or that thing that went missing]
yes, you can ... [do/eat x or y thing you would prefer not to do.]
sometimes we have to do things we don't want to do.

but really, my all time favorite is "you're a silly goose." i'm finding it's a little like "bless your heart" - i can use it when i'm both frustrated, genuinely amused, and whatever combination of the two.