Is that ok to celebrate with Winter Bash on Stack Exchange?
Stack Exchange invites you to celebrate the end of a great year …with HATS! As you use your site, you'll discover hats and other items hidden behind certain actions. Collect all of them, some of them, or none of them, but be quick – the hats get put back in their boxes on January 9th!
And is it ok to wear a hat, like I do now?
Wearing a fictive hat for celebrating the end of a productive year has nothing to do with isa or with any pagan feast. It is not very different from the score and badges that appear, the only difference being that they won't appear anymore in a few week.
Unless your relation to the hats, or the site SE becomes such that it can be considered shirk, as the other answer would suggest, you are safe. If you do in some way worship the hat / site, you have some serious introspection to make...
