Should you leave your job for that reason alone, that you got passed over for a promotion two years in row? No. It's time to look inside yourself and see what you want out of life. By that I don't mean move on because you're not going anywhere.
It is a badge of honor to stay employed at one job for a long time, so consider that. One of my best friends couldn't read or write, but he kept his first job stocking groceries for a food chain for 25 years.
When the chain finally shut down, he had no job, but he had a 25 year work record. He was freaked out but found a new job quickly because he always stuck to his job.
It's been 3 years now & he still has his 2nd job. Think about it. If you enjoy your job stick with it. Don't leave a decent job without a decent reason.