They can be very real, especially lucid dreams. You see, hear, feel, etc. just like you do in real life. The only difference is that when lucid, you have control over what you see hear feel, etc. But you will have genuine emotions, see very vivid imagery, and probably be fooled most of the time. It's not how you see your dreams, but how you see reality that will help you become lucid. Good luck and don't be fooled!