When I was a kid, December 25th is nothing but my birthday. Most of Thai people are Buddhist so we don't celebrate Christmas. Nowadays, Thai people are getting crazy about Christmas more and more. We see it as a festive event, especially in Bangkok. Many places are decorated in a Christmas theme and we can hear Christmas music almost everywhere.
I think this year is overly because there is a 'Santa Village' gift shop opened in a shopping mall here. They sell all Christmas stuff and let us take photos with Santa Claus from Finland. Unfortunately, we have to pay 600 baht to take a photo with Santa or get a 50% discount if we apply to be a member which cost 300 baht. They said it's cheaper than flying to Finland but I don't think it's worth enough. This shop is open all year but Santa flew back home since Dec 25th. I hope they do well with this business and bring Santa to my office next year so I can take photos for free. LOL