When I was younger, honesty seemed unnecessary and anti-social. People pleasing was important and so honesty seemed scary. With years, as my bullshit radar got more sensitive and ego shrunk, as I came to rely less on what others thought of me, I came to appreciate honesty.
Honesty with yourself and others makes everything simpler. The less details of your intricate lies you need to remember, the less anxiety you experience. Dalai Lama famously said that he can’t keep any secrets, which is one of the reasons why he is so happy. Honesty is the ultimate lifehack, pinnacle of minimalism, test of what and who truly belongs in your life.
Honesty with yourself leads to progress, to stopping bullshitting yourself and finally taking the action or appreciating the price you will pay for never doing it.
No need to be a royal asshole and upset people, you can be honest and pleasant at the same time. Eg if you have to, you can compliment anyone, even the worst person, by finding their most outstanding feature or attribute and speaking honestly about it. If you have to serve truth, do consider whether you took into account all points of view and whether you have sufficient facts (you may be wrong!) and if you are confident with your opinion or perspective, devoid your message of emotions and base it on the facts. Be humble and be compassionate, this will save you from being a jerk.
Radical candour is bitter but useful, like a reset button. Exercise with caution and receive it as willingly as you administer it.
Nomad of the Universe 
Pingback: Advice I would give my 20 year old self #happiness | Nomad of the Universe