孤酒怪友老酒识友
[gū jiŭ guài yŏu lăo jiŭ shī yŏu]
Roughly means 'lonely wine makes strange friends, old wine knows (true)friends'. It refers to drinking alone can bring about acquaintances, possibly under odd circumstances or states of mind; however only with familiar habits (like an aged wine choice), genuine friendships become more evident over time.