ใจเย็น, the highest praise, and ใจร้อน, the gentle criticism

If you collect one compliment in Thailand, make it ใจเย็น, 'cool-hearted': calm, patient, hard to rattle. People admire it in bosses, drivers, teachers and partners. The opposite, ใจร้อน 'hot-hearted', is impatience: honking, sighing at a slow queue, raising your voice at staff. You rarely hear it as an insult; it comes as a gentle diagnosis, often about oneself: ผมใจร้อนไปหน่อย 'I was a bit impatient'. When someone says ใจเย็นๆ to you, take it seriously: your tone has already crossed a line, and calm is now the fastest way to get what you need. A raised voice costs everyone face, including you. Explaining a problem slowly, with a smile, reads as competence.