Wash car - scratches

Everytime I try to was someone's car that they've lent to me for a few days.. I notice scratches...

I know if there's sand in the cloth it does that.. I've googled and tried my best how to remove them, there's colgate, etc... Polishing and rewaxing..

But yeah...

I.. Never learn my lesson.
There's always sooo much regret after doing it, washing someone's car.

Like... Before I wash it, I think to myself, what could go wrong?

And everything does. Once the water dries up, and the scractes don't have the liquid in between the grooves to refract light anymore. They start showing.

Gahhhhh

Every single time!

So much regrets. Probably one of the biggest regrets I have about my life all the time.

I think I'm not going to wash other people's car anymore. I'll just bring it to the car wash next time.

Hopefully I remember this.