Korean food? Oh can I come to your house? Please... I love kimchee, and that hot pot bowl of rice and a bunch of other stuff served wiht the egg on top...
When you are cooking the pasta, the water should be very very salty, it's the only time I ever use salt in cooking, I will throw in a handful of salt into a large pot of water. You also want to make sure that there's plenty of room in the pot for the pasta to cook. and experiment wiht the cooking time, I prefer pasta al dente, so it's got a little bit of firmness in it.
I've seen a lot of recipes that suggest some oil either in the cooking water or after the pasta is cooked, oil i've found, prevents the sauce from clinging.
What I'll do, is throw the spaghetti in the sauce for about a minute while it's still on the heat, it finishes cooking in the sauce and takes on a great flavor.
Jarred sauce? I've never found a good one, Paul Newmans Aribiatta is about the closest I've seen. ("I've lived in Guidoville too long, jarred sauce would get you evicted from North Jersey
Fresh parmesan cheese - get yourself a hunk of the cheese and a grater, and it will make a world of differene (it's expensive so don't share that with the dog)