When you say "I need" it comes from the vibrational standpoint of not having, which simply means that your attracting into your life more of the I don't have. For instance; if you find yourself saying in a frantic, fearful voice, "I need money", the universe responds to the vibration of lack and scarcity and keeps delivering exactly that. On the other hand and at the polar opposite of the spectrum you have the phrase "I want". Now say to yourself, "I want more money". Can you hear and feel the difference between these two simple phrases? The universe hears and responds to your wanting of more money and delivers just that, more money.
Everything in the Universe is energy and energy has a vibrational frequency. Your language patterns and emotions tell the story of what you're attracting into your life so pay close attention to the words you use and the emotion that resonates from using those words. If you feel you need something then ask but make sure you then consciously shift your vibration in order to allow it to flow into your life.