Bitterness produces it’s own fruit.
Even scientifically in the brain through neurogenesis and explained further through psychology, negative thoughts produce neurons, chemicals, attitudes and ultimately outcomes in your life consistent with persistent thought patterns.
You do experience what you think… And in the case of envy and bitterness you set yourself up for failure, many times before you have even begun.
Philippians 4:8 New King James Version (NKJV)
8 Finally, brethren, whatever things are true, whatever things are noble, whatever things are just, whatever things are pure, whatever things are lovely, whatever things are of good report, if there is any virtue and if there is anything praiseworthy—meditate on these things.