An Etymological Dictionary of the German Language/Annotated/gefallen
gefallen, verb, ‘to suit, please,’ from Middle High German gevallen, Old High German gifallan, strong verb ‘to happen, fall to one's lot, please,’ in Middle High German always with the complement ‘wohl’ (well) or ‘übel’ (ill); probably an expression derived from the Old Teutonic warlike custom of dividing booty (compare Hund) by means of dice; es gefällt mir wohl, ‘I am well pleased with it,’ literally das Los fällt gut für mich, ‘that was a lucky throw for me’ (a similar history is also connected with Modern High German schenken, which furnishes evidence respecting the Teutonic drinking customs). Note too that in Modern High German terms relating to card-playing have been similarly used, Compare Sau (literally ‘ace (of cards)’ then generally ‘good fortune’) and Hund.