Spreadsheets suck for "what if" stuff. Change one cell and the whole sheet dies. I built a browser toy (Datastripes) where you can flip variables and watch the

Spreadsheets suck for "what if" stuff. Change one cell and the whole sheet dies. I built a browser toy (Datastripes) where you can flip variables and watch the charts shift in real time. No installs, no backend. How do you all stress-test ideas fast? Stick to Excel, code, or something lighter?