> Add a small amount of olive oil as extra help for that
It really doesn't. Oil doesn't mix with water. The only thing it does is oiling your pasta when you drain the water, which prevents the sauce from sticking correctly.
Pasta naturally don't stick together if you use a pot large enough, with enough water. And even then it doesn't stick, I honestly don't know how people make their pasta stick.
Cheap pans. Thin-walled that doesn't distribute heat evenly. So hot spots burn the pasta to the walls.
Secondly, not stirring at all. Boiling will do some circulation, but you have to keep some amount of stirring to prevent a small sticking turn into a burned to the pan problem.
