What do I wish I had done today?

I wish I told someone what I think of them!
sounds silly but I'm sick of being afraid of telling people my honest opinions about them. One person for start (who'll I'll name John) John is a complete self absorbed Prick, who thinks he's all high and mighty because he's older and more "acomplished" yeah sure a job you took beacause your only talent is pleasing yourself! He talks to his family like shit but acts all nicey nice around other people, his priorities are totally messed up and gives no consideration for how other people feel, his family members can't stand him half the time and are glad when he's not around! Also he is a smug arrogant fuck-tard who uses his masculinity to dominate things!

Now lets say I told John this to his face, I'd get a slap, but if I gave him a watered down version of the truth I'd become a stupid oppiniated teenager with no respect! Half the people I know I can't stand but I can't be bothered to argue with them!