When I was working you could always tell the children who were allowed to get away with pretty much anything. It seemed like they had never heard "No, you can't do that" or "You have to wait it isn't your turn" or any of those types of phrases that let children know the world does not revolve around them.
Now I realize that at the age of 14 months... yes the world does pretty much revolve around Blake, but we are working on... "Stop! That isn't yours", "Stop! That's not safe" and similar phrases. Yes, I do use the word "No", but I try to tell him in another way first and then it's "No!"
Trust me, when Blake gets his mind set on something NOTHING stops him. For example, lately Blake has been wanting to play under the kitchen sink. Now, it's not what you think... there is nothing under there that could harm him. But, there are all these neat pipes and hoses and stuff. When he gets under there he used to just sit there and look out into the kitchen... that was fine. But not now, now he gets in there and shakes the pipes... and HARD! So now we are trying to stop a behavior that used to be ok... that is hard!
Today he climbing in under the sink. I walked over and said "Please come out" Yeah he looked at me and laughed. I then took his hand and said "You need to come out of there" while gently pulling him out. He comes out without a fuss, but is then trying to get back in within seconds. So, I stand so he can't open the doors. Well let me tell you, you'd think I smashed his hand in the door or something. He starts screaming and crying and carrying on. I get back down to his level and tell him.. "you can't play with the pipes". I stand up and say "Let's go play with the trucks". No go! Distraction doesn't work with him.
Oh well, we will continue to try. But, we will not give in!! I figure sooner or later he will realize that when I say no... I mean no!