Human beings are just sacks of blood and flesh with tons of emotions running through them. On 9 out of 10 days, the words mentioned in an Oxford dictionary are enough to express those emotions.
On that one day, however, said words are not enough. especially for our generation. I mean, we deal with shit that most people haven't even heard of. Which is why we have the Urban Dictionary.
It does make expressing your feelings easier, doesn't it?