That surely is strange that someone told you that. Normally you would expect the opposite, that laughter and happiness etc. is good and healthy, but anger isn't. However all emotions are important to some extent.
I guess everyone deal with their emotions differently due to how they were brought up; how the people around them discussed emotions etc. Some can be spoiled and over confident, some always feeling down, and some emotionless.

I would think that it's normal that you grow a bit emotionless after someone kept telling you that- I see it as some sort of conditioning, 'training' you mind to think and feel a certain way.