You are a "Top Contributor" to this forum and you need to ask this question? Seriously?
You're in Malaysia and you didn't need it when you entered? You have to be joking, right?
For a Tourist Visa most countries ask for your Travel out. Yeah, when I first started traveling I thought it was strange also to need to plan your exit in advance. It is what it is. But you're not a first-time traveler are you? You bill yourself as a person who travels a lot.
What gives? Are you drunk?
Have you always just been stamped in and were lucky enough never to have been asked for it?
If you are patient, the Dollar generally goes up against most currencies. Now is not the time to bet against the Baht though. They are still recovering from COVID despite the Thai Government Bureaucracy's best efforts to trip up the economy.
You can wait a long time if you bet against the Euro or Brit Pound vs USD though.