The dandelion is the flower that is the epitome of unsolicited happiness. They are bright and yellow and round and would likely be quite respected were they not so numerous and uncontrollable. However, their not being able to be contained is what I think makes them so interesting.
In this world, we hear of happy people but rarely is anybody perpetually happy. Now that I think about it, neither are dandelions – they turn grey and lose their seeds – but the dandelions still but on a better show of joy than we do. So many people mop around, being completely ungrateful for everything and unwilling to truly live. These people need to be more like dandelions, shining bright and colourfully all the time, for the world is an amazing place, and they shouldn't try so hard to be unhappy.
Correction: I will never advocate for people to be happy 100% of the time, for this would deny human nature and also devalue happiness. I will also never say that people should pretend to be happy when they're not. The key is to know when you are actually unhappy and with a valid reason to be so. Quite often, people will convince themselves and others that they are unhappy because they enjoy when other people comfort them and quite honestly because their bodies have formed a chemical addiction to the feeling of sadness.
If you are only pretending to be sad and are not truly sad (and don't forget that you've likely tricked yourself as well) then there is a great deal to be gained by being like a dandelion. Glowing proudly will help to raise you out of your misery and onto happiness! Shine it!