Sleeping with my head under the pillow.
Weighing myself before and after using the toilet.
Writing with propellor-pencils.
Commentating aloud, whenever watching sport alone.
Wearing two pairs of socks at once.
Cleaning my ears, even though they're already clean.
Re-reading books multiple times, rather than wasting time starting new ones.
Working out the publishing date of maps by what countries were in existence.
Preaching to myself when alone.
Cleaning under my nails with the page-edge of whatever I'm reading.
Hope you found that enlightening :)