When you feel like you’re making progress having to then take a step back is a big deal. It feels like you’ve wasted your efforts but more importantly time that you can’t get back.
But if you change your perspective, those steps back could actually be a good thing.
Perhaps you were heading down an unhelpful path and now gain clarity.
I think the main thing is to understand that a setback doesn’t stop you from reaching your end goal it just changes the path you take to get there.