According to the German government, the Like button violates Germany’s prohibition on tracking people’s movements on the web. Fines might be levied against Facebook and potentially against websites that are based in Germany.
In addition, Facebook tracks what you do on their website. It all goes into their method of deciding which of your friend’s updates and what ads to show you. (And despite scams saying you can discover who viewed your profile, there is no way for anyone to know that except Facebook.)
Can your Facebook account get you fired? It’s been done and the appeals are under consideration.
Also, you may have run a contest on Facebook or some other social media.
There are a lot of benefits of having a sweepstakes or a contest, so you might have asked for a Like, an email address or a phone number, all of which could be considered something of value. If you didn’t return something of value in exchange (not just a chance to win) then you might be running afoul of lottery laws. Be careful and protect yourself.