I’ve also seen plenty of web apps which load slowly because they load too much javascript. Most of it unused. I was asked to help out with one project my cowork

I’ve also seen plenty of web apps which load slowly because they load too much javascript. Most of it unused. I was asked to help out with one project my coworkers were working on where the bundler was pulling in multiple copies of momentjs, each complete with its own copy of the global time zone database. The page loaded way faster once we cleared that out. A few years ago I noticed most websites just seemed slower than they should on my computer. The culprit turned out to be metamask (an etherium wallet extension). It was adding 700 kilobytes of javascript to each page load thanks to web3. It also exposed my etherium address to any website that asked. The JS was cached, but just parsing that much code added noticeable lag to every page load. Everything felt zippy once I uninstalled that.