Don’t underestimate this common coding mistake: ignoring edge cases.
Most bugs don’t come from your main logic — they sneak in through what you didn’t think about.
Empty inputs, missing data, weird user behavior — that’s where things break.
You build a login form? What if the username is blank… or 300 characters long?
Great developers don’t just write code that works — they write code that fails safely.
Test the edges, not just the happy path.
Because the users? They will find what you forgot to handle.