Little is more annoying then standing in front of a vendor that is supposed to be open, but is closed. You’ve spent time looking it up or got a recommendation from a friend, spent your time and money on a taxi to get there and is eager to dive into the goodies you’ve prepared for. Then you arrive, just to find out it is closed due to public holiday.
Many street food vendors and local restaurants in Bangkok/Thailand are closed on public holidays. Few of them tell you about it and google is never updated on local holidays. Of course there are vendors that are open, but public holidays are not the day you should put an effort in traveling to fin out.
An easy way to not go in the public holiday trap is to check before leaving for your exploration. The web page time and date is excellent in that respect. You just enter the site and the info is all there up front without another click.