No, means what exactly?

So I say NO, NO, NO, NO. I read the other day an article about what words moms shouldnt say. Besides the obvious 4 letter ones, there was Hate, Stupid, Gay, a couple others I cant remember and NO. No really? We cant say NO, they what do we say? Yes? "Mommy can I play with the electrical socket?" "Why Yes dear, go right ahead..."
I am all for trying to let our kids grow in a world where they learn right from wrong by doing, but really NO is a word we shouldnt say now?
I say NO probably over 1000x in a day, which sucks. I hate, opps...dont like saying NO. It doesnt sink in, and they dont understand what No means.
No, you cant take that toy outside, No you cant have ice cream for breakfast, NO I am not buying sugar cereal(I know Im a mean mom), NO, NO, NO!!!!!
I want to say why dont you be the mom and I be the child? You can tell me no, No mom I dont want to, No mom Im busy, NO mom I wont eat that. I hear it, I understand it. I remember, uh she said NO, she didnt like spinach so I wont serve it again. But when I say NO, to the same question for the 1000th time, when does No sink in?
Is there another world instead of NO, another way to make the NO reason sink in? I am not a mean mom, we just cant buy everything they see...and so once again I am forced to say NO...but I want so badly to say YES.
Yesterday we were in the grocery store, after our trip to target and whole foods. In target a few 'I wants' were asked, I had to say no. I want this candy, NO, I want this easter basket(we already have 2) so NO, can I buy this its only 4.65...NO. I try to explain why, but before I can say because it is off to a new want or NEED.
The thing is I am not sure I had half the things my kids do and I was only 1. I definately had my share of stuff dont get me wrong, but mine have 2 of each(most things) if he gets a bean bag chair, she has to have one...its not my mentality but my mom always buys in 2.
Now with baby 3 on the way, will we become in 3s? Teighan wants a paddleboard, do I end up buying 3? How do you reinforce that there are times it is for Koda, times things are for Teighan and now going to be times just for the baby?
Yesterday before our excursion we were at soccer, and Teighan expected a snack(he is not on the team he is the brother of a player on the team). When he didnt get something he got extremely upset. I try and try to explain that sometimes things are just for her, but it doesnt sink in.
Back to the grocery store, we were in the cereal isle, they want so badly to buy the sugar cereal(lucky charms, cookie crisp...) I again am not a mean mom. I have bought these, and I have thrown a whole box away. I learned my lesson, you dont like them, and I hate, opps...dont like cereal at all. So No, the NO's were flying like a drunkin sailor shouts out profanity...I even left, my cart and all right there and decided to leave the grocery store. Of course we had breakfast today, so I caved and went back in to get the groceries we needed...
When is enough enough? I went to bed last night so upset with them and myself, trying to reason with a 5 and 6 year old isnt working. Only causes me much unnecessary stress, but shouldnt NO be enough?