My job is too demanding and I do not have time to serve on a jury. Do I still have to serve?

Yes.  A summons is an official court order compelling you to appear for service.   Jury duty, although sometimes inconvenient, is not an optional experience.  Jurors should also know that following Michigan law:

600.1348 Jurors; threats, discharge, or discipline by employer; requiring additional hours of work; misdemeanor; penalty.

Sec. 1348 (1) An employer or the employer’s agent, who threatens to discharge or discipline or who discharges, disciplines, or cause to be discharged from employment or to be disciplined a person because that person is summoned for jury duty, serves on a jury, or has served on a jury, is guilty of a misdemeanor, and may also be punished for contempt of court.