The mind is a powerful thing. It conjures up unwanted thoughts that are so tenacious that, try as we might, we cannot shift them. It defines our perception of ourselves and our surroundings, even if that perception is harmful. But you can banish those thoughts and change the way you view the world, using that same power of the mind. All it takes is a few tweaks, says clinical hypnotherapist Laila Saif.  A simple exercise...