Awhile back we told you how to get rid of negative thinking. Along the same lines come a post from Creating Passionate Users about how the negative thinking of others can affect you.

There is now strong evidence to suggest that humans have the same type of "mirror neurons" found in monkeys. It's what these neurons do that's amazing—they activate in the same way when you're watching someone else do something as they do when you're doing it yourself! This mirroring process/capability is thought to be behind our ability to empathize, but you can imagine the role these neurons have played in keeping us alive as a species. We learn from watching others.

Negative influences can be pretty bad for you it seems.