I Joined My First Job and the Homepage Took Forever to Load

Thinking back to my first real frontend job still stings. I wasn't a total coding newbie—I had a CS degree and plenty of full-stack school projects. But professional work? Zero experience. No production traffic, no performance budgets, and no QA breathing down my neck about real users bouncing. When I joined, the e-commerce homepage felt brutally slow. QA kept dropping the same messages week after week: "Homepage lagging again 😭" "Hero + product grid take forever." "Users are leaving because of the 3s+ delay." I'd open the reports, see those agonizing waterfalls, and just feel paralyzed. The stack looked modern on paper: S3 + CloudFront + Single Page App (SPA). To make it "modular," we used iframes for sections like recommendations or banners. In theory, it was plug-and-play. In practice, it was a heavy, fragile mess. I could sense something was off, but I didn't have the vocabulary yet to explain why: every iframe was exposing a massive, redundant dependency graph that our monolith h