Your teen walks into the kitchen while you are preparing dinner and says; "I need to go to Staples, or all my jeans are dirty, I need my laundry washed, or I'm going to Dan's house and I need a ride, and so on and so on and so on. So from their point of view, their needs and wants take precedence over anything of importance that you are doing. God forbid you have something else to do and say: "Honey I can't, I have to......fill in the blank." Or maybe you hear one of these statements and get aggravated. How dare they think that you will just be at the beck and call, have they no respect? You say as much, and an argument follows, with your teen totally not getting why you are aggravated. After all, isn't this your job to be at their beck and call?
This interaction probably happens between you and your teen a million times a day. So often that perhaps you are so immune to it that it doesn't even register as a demand unless they catch you at a particularly bad time when you are overworked, overwhelmed and overtired and can't handle one more demand from anyone. Then the sh**t hits the fan, and your teen blames you for being a bitch!
Without being aware of it you may have reinforced your teens demandingness. Because teens are by nature, and by this I mean biologically, self-centered, and truly only think about themselves. They are often completely unaware of someone else's perspective, as their brain is filled to the brim with all the new thoughts, feelings, and desires that adolescence delivers. This isn't really about a bratty kid or a spoiled teen, at least not the teen I am talking about. You may in fact have a spoiled, bratty, entitled teen, but that is a result of overindulgence, not biology. I am talking about your normal, everyday, developmentally caused demanding teen. They just need to be taught to ask a question, rather than make a statement of want. You don't need to criticize, you need to re-train. And here is how. Every time your teen comes to you with the "I need you to, or I want you to, or you have to...." You can calmly say: " Is there a question in there?" No giving answers until they put their demand in the form of a question, giving you the opportunity to agree, or not agree based on your availability, and your desire to do or not do what they need. Everybody deserves the respect of choice. That includes your teen. So what's right for your teen, should be right for you as well. Rather then demand they help you, or fulfill an obligation, as in " take out the trash ...now! or Shut off the computer, and do your homework!" which they probably avoid or ignore you anyway, why not model with a "honey I could really use your help with trash, will you help me? " "Honey, can we come up with a time you'll get off the computer and do your homework." It still might not work, a power struggle is a power struggle, but at least when they demand something and you tell them you won't respond to demands, you won't get sucked down the black hole of "well you just demand things of me, you never ask me nicely, why should I have to ask you nicely." Which of course turns into the old, I am an adult, and I can tell you to do anything I want lecture. Which of course never goes well.
If you can just see this as a teaching moment, like teaching your toddler to say please and thank you, you'll be on easy street. It will make you like your teen a lot more. And remember practice makes perfect. This might take a while.