Cut celery and onion (and bell pepper if used) as fine as you prefer.
If you like chunky style sauce make the pieces bigger, I like mine chopped fairly small.
In a large skillet, heat 1-2 tblspn of oil, when oil is hot (not smoking) add celery and stirfry.
As celery begins to clarify, add onion (and bell pepper, if used) and stirfry until it begins to glaze, add chopped garlic, stir for a short time (don't let anything begin to brown).
If using meat, add ground beef or stew beef and brown, stirring regularly, adjust heat to make sure nothing burns.
Salt and black pepper to taste.
Transfer to a larger pot (if you have a good sized pot that you can brown in, you can just start with that instead of using the skillet.).
Stir in tomato paste and cook until the color darkens.
Stir in tomatos and tomato sauce.
Add spices (Italian seasoning or individual spices) to taste.
Add 3 Bay Leaves.
Stir in mushrooms and/or black olives and crushed red pepper, if desired.
Stir in 1-2 cans of water (I use the tomato paste, tomato and tomato paste cans to get the leavings out of them.).
Adjust heat to simmer.
Let cook for at least 1 hour, longer if you can, and stir regularly.
Check spice to taste and add what you want.
You can cook this for a little while or for a longer time.
I prefer at least 2 hours to give all the spices a chance to blend well.
But it can be cooked for as little as a half hour.
If you want it to cook for a long time, monitor the thickness and add water as needed.
Don't forget to remove the Bay Leaves before serving.
Some people like to add a pinch of sugar to cut the acidity, but I believe that the Bay Leaves accomplish this and have never used sugar.
When done, serve over or mix with the cooked pasta of your choice.
Add grated parmissan if desired.
Also individuals can add crushed red pepper to their own servings, for those who like it a little spicier.
If making a baked dish such as Lasagna, Ziti, etc.
you may want to make the sauce a little thinner (add water) to start with.