You shouldn't leave an employer in a bad situation.
Nyssa is the manager at a mom and pop owned grocery store, and has been offered a job at a bigger retailer.
Nyssa wants to take the job with the bigger retailer.
Nyssa gives a two-month notice to her employer before moving on in her career.
Nyssa leaves her job for the bigger retailer without informing her employer.
Nyssa's employer is able to find her replacement, and she moves up with her career.
Nyssa's employer is left scrambling for months trying to find her replacement.