В радости сыщут, в горе забудут

Many people seek your company when you are happy, but when in grief, you are left alone to bear the hardships. See В слезах никто не видит, а в песне всяк слышит (B), Скатерть со стола, и дружба сплыла (C)

Cf: Adversity has no friends (Br.). Feast and your halls are crowded (Am.). In time of prosperity, friends will be plenty; in time of adversity, not one amongst twenty (Br.). In time of prosperity, friends will be plenty; in time of adversity not one in twenty (Am.). Laugh and the world laughs with you; cry and you cry alone (Am.). Laugh and the world laughs with you; weep and you weep alone (Am., Br.). Smile and the world smiles with you /; weep and you weep alone/ (Am.). When good cheer is lacking, our friends will be packing (Br.). When we laugh, everyone sees; when we cry, no one sees (Am.). When we sing everybody hears us, when we sigh nobody hears us (Br.)