One thing you can't pretend to be is funny.
Shortcuts aren't always.
The teacher can always tell when you did your homework on the bus.
You don't get to decide your part in the school play, but you do get to decide whether or not you play it well.
You'll have a lot more respect for a bird after you try making a nest.
It's not enough to be able to spell "magnificence" in your bedroom. You have to be able to spell it at the microphone during the spelling bee.