Bad is stronger than good. It is more important to eliminate the negative than to accentuate the positive.
Robert I. Sutton, “12 Things Good Bosses Believe“, Friday, May 28, 2010

There are interesting discussions in the comments on that article where people express finding the expression negative, and their need to focus on the good.

My interpretation of the expression is that it speaks to the power of bad to overwhelm good.

I can’t enjoy the good with bad present.

For myself, negative energy causes me to stumble. It drains me. And then I also become a conduit of the negative energy.

For me to reach higher I need to be surrounded by people feeling it, and supporting it.

Only in a positive, empathic environment, am I able to be my best.

"In Flames - Koh Tao june 2008" by Bart Hiddink, cc-by 2008