Adults are just better at pretending. They pretend they like things they don't, that they don't care when they do or that they are happy when they are not.
Adults lie too. They just get better at covering it up. In fact, adults lie to themselves more than they do to others. They just get better at believing themselves.
Adults make mistakes. They are just better at rationalising their way out of it.
Adults make mistakes. Constantly.
Perhaps the only comforting thought is that wisdom doesn't come with age, it comes with experience. At least this way, you learn to forgive adults.