Is It Normal to Have a Bad Day?

Is it normal to have a bad day sometimes? Like some days you're good and then suddenly one day like your English is terrible. Is this normal? Why does this happen? Yeah, let's talk about it. This spectrum of ability. There's our first word spectrum. Spectrum means range range, right? Not one point. But we can also call that a spectrum. It's a kind of range. These good days and these bad days is a normal 100%. 100% normal.