oddity, queerness, crotchet, quirkle, kink, quiddit, kinkle, quibble, quippet, quiff, more...

norm, normal, regular

personality quirk, physical quirk, quirk of fate, quirk of nature, more...

strange, little, odd, curious, personal, psychological, peculiar, interesting, mental, mere, statistical

minor aberration,   unique mannerism,   peculiar mannerism,   behavioral quirks,   odd fancy,   weird kink,   annoying habit,   unusual tendency,   unusual way,   strange habit