When I was a new parent it was important for me to always explain everything to my children as well as I could. If they had a question, I would explain. If I wanted them to do something I would explain the reason. My oldest, being very precocious, quickly realized that this was a way of getting out of doing something. If I asked her to do something and she asked why, then after I explained if she were to again ask why, she could put off whatever I wanted her to do for a very long time.
Wanting to keep my initial intent of being willing to explain things to my children I decided I needed to change my game plan just a little. When she would ask why, I learned to say, first comply then ask why. When she was doing doing whatever I had asked her to do, I would then ask if she had any questions. Usually she did not. As my four children grew older they usually preferred to avoid my long explanations, not just about reasons for doing things but about all kinds of things, so they asked even less. I finally learned to ask, if there was a question, if they wanted the Reader's Digest (short) version or the long version. Usually they only wanted the short version. As they continued to mature, one child in particular; but two to a greater and greater extent, started to request the longer version and instead of a lecture we developed wonderful discussions which I enjoy immensely. It is a wonderful blessing to have in depth conversations with your children, which to greater and lesser degrees I'm now able to have with all of my children. The best conversations are those where we both learn something from each other and where sometimes, something said by one of children, causes me to gain greater insight and understanding.
Be willing to discuss and explain things to your children. If you do not have a good reason for something, them perhaps you need to change the way you think and do some things, or at least you need to be willing to find out for yourself so you can explain it to your children.