Have you ever worked in a system that didn't let you do something? Did that leave you frustrated and wanting to rant on Twitter? This talk will help you cope with that frustration by showing you the number of wonderful things constraints provide - performance, security and ease of change. We will show examples from TypeScript, Bazel, and Angular where the tool/frameworks critically rely on the *inability* to do something, to allow even better outcomes. About Rado Kirov Rado works on the TypeScript infrastructure team in Google. Previously he worked on Angular (when it was still called Angular 2) and AdSense. At some point he tried to do mathematics for a living, but then thought better of it. Premier Sponsor: ag-Grid (ag-grid.com).