In the U.S., dismissals are for anything that would prejudice you against either party and "time considerations will do just that" (if you're concerned about missing work, it's a good reason to get off, though salary work is not likely to have such a concern as your payed yearly regardless of time worked... most salary positions in the U.S. will recognize "jury duty" as valid leave).
You don't have to pretend to be a libertarian to know about "Jury Nullification" as it's hardly a Libertarian view, though U.S. Libertarians tend to discuss it as they are minarchists and believe the government has been overextended glut (though not out and out uneeded like there European cousins who tend to be anarchists... and not in a legal system that uses juries).
When a prospective jury do not lie while being voir dired (the term for the jury selection questioning), the jurist is under oath, which means that any lie you tell opens you up to perjury charges. As much as you don't want a seat in the jury box, you really don't want to be sitting at the defense table.
Most lawyers will dismiss anyone who shows signs of knowing anything about the case or the law (or thinks they know about those). Unless it's a high profile case, you're likely not going to have any knowledge about the defendant or the crimes or even if it's criminal in nature (U.S. uses Jury trial for civil cases as well). And remember a "Jury of the defendant's peers) are your peers as well... you don't want to call yourself a bigot of any strike in a public record only to have another potential juror come into your work, see you, and ask for your manager because the juror doesn't like bigots and won't do buisness with someone who says under oath they are nor there employers (yes, Karen can get summoned for Jury duty).
Edit: Fun Fact, in the U.S. you can't really serve on a jury if it's a capital punishment case and you are opposed to capital punishment. In a few, the jury will actually be relevant in the sentencing phase.
