However, not being able to explore such feelings ends up making you an unsympathetic person, as you cannot bare these feelings with others.

Another argument is that you are denying yourself of the experience of being human. These feelings exist for a reason, just as physical pain exists for a reason. You wouldn't hurt yourself on purpose (or maybe you do c;), but physical pain helps you stay safe. I feel this is the same purpose of negative feelings.

Finally, I have found out that suppressing these feelings does not allow you to fully process and heal from the events that trigger them.