Dry-wiping dust off the paint
UAE dust is largely silica, harder than clearcoat, and dragging it with a dry cloth or duster sands the surface. It is the single biggest source of the swirl marks people later pay hundreds of dirhams to polish out. Dust either gets rinsed off with water and lubrication or left alone until it can be.
Pressure-washing the engine bay at home
Water driven past connector seals into coils, the alternator or fuse boxes causes faults that surface days later as corrosion develops, which is why the damage rarely gets connected to the wash. Bays need degreaser, brushes, covered electronics and low pressure or steam — a job for someone who has done it a few hundred times.
Polishing too often
Every machine polish removes clearcoat, and clearcoat is a finite budget of roughly 40–60 microns for the car's whole life. Cars that get 'a quick buff' at every service end up with thin, UV-vulnerable paint within a few years. Protect more, polish less: correction should be an occasional reset, not routine maintenance.