Mindfulness helps us freeze the frame so that we can become aware of our sensations and experiences as they are, without the distorting coloration of socially conditioned responses or habitual reactions.
The present moment is changing so fast that we often do not notice its existence at all. Every moment of mind is like a series of pictures passing through a projector. Some of the pictures come from sense impressions. Others come from memories of past experiences or from fantasies of the future.
You can't ever get everything you want. It is impossible. Luckily, there is another option: You can learn to control your mind, to step outside of the endless cycle of desire and aversion.
Let come what comes, and accommodate yourself to that, whatever it is. If good mental images arise, that is fine. If bad mental images arise, that is fine, too. Look on all of it as equal, and make yourself comfortable with whatever happens.
The brain does not manufacture thoughts unless we stimulate it with habitual verbalizing. When we train ourselves by constant practice to stop verbalizing, the brain can experience things as they are.
Whatever attitudes we habitually use toward ourselves, we will use on others, and whatever attitudes we habitually use toward others, we will use on ourselves.