Jury duty varies from county to county. If you are in a county where the jury clerk allows for flexibility, that is great. But in some counties if you are a smart a**,
you can get into big trouble. You could be found in contempt of court and spend time in jail or on a work crew cleaning toilets each weekend.
In my county, you have to serve. You can reschedule, but you have to serve. Sometimes if you have an unusual excuse or are being a smart a**, you will get a writ requiring you to appear before the judge and explain yourself. If you are found to be lying by the judge, that is perjury.
Bottom line. Be respectful.