The difference between one letter or two letters; writing with a "SHINUI" (not the usual manner).
One letter on top of another letter.
Using Bug Spray on Shabbos;
Giving a gift. (Understanding how that concept works).
ממצוא חפציך (Mimtzo Cheftzecha): Why Do We Need Both 'Recognizable' and כוונה (Kavana)?;