When you:
Use the rankine scale.
Memorized all U.S. Presidents
Are excited to take the SAT and ACT
Love politics.
Memorized first few scenes of zootopia.
Memorized most of the first episode of Futurama
Memorized most of the first chapter of "The lighting thief"
Know the meanings behind NOR, OR, NOT, XOR, AND, NAND, and XNOR
Use the Oxford comma
Use bulleted lists.
and more!