If you didn’t sleep well last night, you can convince yourself that you did just by believing you aren’t tired. It’s called ‘placebo sleep,’ it improves cognitive function, and it makes you perform better than when you spend the day thinking about being tired. (, , )

Your lie will be more convincing if you have to pee when you tell it. Because of a phenomenon called the ‘inhibitory spillover effect,’ the need to control your bladder also forces your brain to activate more self-control, which helps hide the tells you have when fibbing. (, )