Extremely prominent lower eyelashes
Lower eyelashes are rarely if ever as prominent as upper ones in Real Life, but in animation, most especially in Anime, this is a semi-common phenomenon. When they appear on a male character, expect him to be Hot-Blooded and Crazy Awesome. They are somewhat less indicative of a female character's personality, unless she has brothers. It almost always runs in the family.
ExamplesManga and Anime