The starch in the water will help bring the sauce together and make it stick to the pasta better. Its more noticeable in a loose or wet sauce, esp. if you want to avoid it turning into soup. “Simple” sauces like Carbonara or Cacio e Pepe arent the same otherwise.

If you keep forgetting to do it, try leaving a measuring cup inside your colander, when you go to pour your cooked pasta in, it should remind you that you need to skim some water out first.

Probably full of tubberware