CodeOpinion: You Don’t Need an Interface for Everything

You Don’t Need an Interface for Everything argues that slapping IOrderService, IEmailService or IPaymentService on every class is overkill when there’s only one implementation. Instead of needless abstractions, you can often get by with a simple delegate, a class override or even clear comments—and only reach for an interface when you truly need multiple implementations or a public API contract.

The video also traces this habit back to how .NET dependency injection is taught, showing you how to break free of the “interface → class” reflex. It even timestamps quick demos—delegates at 3:25, overrides at 4:33 and comments at 6:30—so you can jump straight to the juicy parts.

Watch on YouTube