Yup. I think one big issue is that a E2E or an integration test is useful on its own, while a single unit test is almost totally worthless. You don't have confi

Yup. I think one big issue is that a E2E or an integration test is useful on its own, while a single unit test is almost totally worthless. You don't have confidence of anything until at least 50% (and at 80% you have almost perfect confidence). So when people get started, especially on an old code base, they feel its pointless and doesn't pay off. Can't blame them, I suppose. Good that you bring up build time. I forgot to mention that. We have repos with thousands of tests where the whole suite runs in <1 minute and gives us very high confidence (actually the only other tests we run on that repo are visual regression tests for CSS, and even E2E tests don't catch those issues...). During that time I'm watching other teams waiting 20 minutes on their integration test suite. Nope nope nope.