How do you know what you look like. You can see your hands, feet, legs and torso. But you cannot see your face because eyes are fix in your face itself. To know what your face looks like you need to look into a mirror. By looking at the reflected image in the mirror you know what you look like. You can also find out about your physical structure and overall features by looking into a tall mirror. As a matter of fact I discovered my bulging abdomen only after looking at myself in profile in a full height mirror.
Think about a time when mirrors where not common. In those days people were not much occupied with comparing their own appearances with others. Instead their perception of their own personalities was dependent on how others reacted to their presence and behaviour. By trial and error they adjusted their behaviour until they felt that others were comfortable with them.
With the advent of the mirror men and women became more preoccupied with their facial appearances and a whole industry of facial grooming for men and women came into existence. Starting with shaving sets and makeup kits, nowadays there are there are beauty salons, parlors and grooming centres at almost every bus stop. On the othr hand a "who cares" social attitude seems to be the order of the day. It seems unfortunate that now a days concern for the feeling of others has a lower priority than one's own appearance.
However in a new wave of evolution we find video cameras commonly available in mobile devices which are frequently used for recording images and actions of others. It would be a good idea to fix a video camera in a suitable location to record your own normal actions and speech. You may be surprised that your demeanor is quite different from what you think it is. Once you know where improvements can be made in your manners and speech it should not be so difficult to develop a more pleasant personality.