Illustration by Mateusz Slodkowski/SOPA Images/LightRocket via Getty ImagesThis post originally appeared in the Business Insider Today newsletter.You can sign up for Business Insider's daily newsletter here.We all know the quote, "Do one thing every day that scares you." For plenty of people, that's posting on LinkedIn.The professional social network is notorious for cringeworthy, performative posts. But those posts also generate a lot of engage…