A cute Thai phrase I just learned is:
คนใดจะชอบคนไหนก็ได้
khon-dai ja-chawp khon-nai gaw-dai
"Any person will love whomever they wish."
The sentiment is obviously very nice but the sound of the phrase is what makes it great
Also:
เพื่อนกินหาง่าย เพื่อนตายหายาก
pheuuan-gin haa ngaai pheuuan-dtaai haa yak
"It's easy to find a friend for a meal; it's hard to find a friend until death."
Or, to be more idiomatic, "Some friends are for a reason, some friends are for a season."