It should go without saying that you should be careful of what you "like" on Facebook. You should try not to "like" anything embarrassing or incriminating, lest it come back to bite you. A judge has ruled that "liking" something on Facebook doesn't protect you under the First Amendment, which is bad news for at least one man in Virginia.
Looks like they were stupid enough to "Like" the political opponent of their boss- basically saying they'd "Like" to see their boss fired. Many people might feel this way but it is a bad idea to say it publicly.