If unwanted guests show up at your door, do you let them in, entertain them, let them stay for as long as they want to and allow them to do whatever they want to do in your home? That's what I thought. [No].
Likewise not all emotions and feelings deserve attention. Giving them attention is accepting them, wallowing in them, wearing it on your face, telling everyone about them and basking in their unpleasantness. Giving them attention is giving them power over your state of mind and well being. And the more attention you give to them, the more they consume you and the longer they stick around.
Don't dwell on negative emotions of any kind. If it doesn't add to you, its not welcome. Do whatever you need to do to show them the door. Even if you have to fake it till you make it, do just that. Coz once you turn on the light, no matter how slow the transition is, light always prevails over darkness.