Thanks for excellent advice! Many stars on your forehead.
All of sudden huge text messaging font on Samsung Galaxy SIII/S3. Settings correct. Reboot. Huge text. Pull battery. Huge text.
This "feature" should have been restricted to SETTINGS, not programmed as a SHORTCUT. People's eyesight does NOT change on a minute to minute basis!
Samsung, you are great but you still have issues. Get a clue. Beta test your new hardware and/or software release EVERY time. AND, your beta groups should be globally and use diverse, AVERAGE users, not tech writers, power users, or anyone who's willing to waste time searching for fixes/work-arounds.