"When I landed in Thailand, I didn’t have a return ticket. Immigration pulled me aside right away. Even though I had already filled out the arrival form online, they made me fill it out again and told me I needed proof of onward travel."

If I read things like this I know already half of the story is missing.

@Andrew ******

I understand it's not a nice experience but I understand why they denied entry and it's totally reasonable and it probably wouldn't be different in any other country.

You mentioned they denied entry because you entered 3 times in 6 months how long were you staying?

@Gerard *************

well I arrived a week ago Suvarnabhumi and the line was very long and it didn't seem like anybody got questioned at all. Didn't matter the nationality. Now it's not a great sample size but this was also my 3rd entry within a year with some more stamps from previous years and nobody asked anything. (even tho I have months of time in between them). Soms of this post here I really doubt it's the full story and I still think if you just a regular tourist you have nothing to fear even if you have like 2 stamps or more.