Did I do something wrong entering Thailand visa-exempt as a Dutch citizen?

I was almost denied entry into Thailand. I am a Dutch passport holder and arrived visa-exempt from Amsterdam a few days ago. This was my first visit since I left in March of this year.

The immigration officer interrogated me. She noted that I had visited Thailand many times, always visa-exempt and getting a 30-day extension. She also told me it’s better to apply for a tourist visa next time. . I’ve always complied with the letter of the law, and never overstayed. In the end, she noted down lots of information into the computer, and asked to see my return flight. I was allowed in. Phew. I asked her if I had done something wrong but she said no, but added that I could be rejected the next time I arrive visa-exempt, depending on the officer.

Now on to my question: Did I do something wrong? I thought the Thai government specifically allowed certain countries to enter visa-exempt to attract tourist and make it hassle-free. Any thoughts are welcome. I don’t wanna risk doing anything bad.