The pocket square that sole furnishing item worn by "stylish dressers" that I feel speaks to ones own individuality just as much as the man's necktie. When you see that small piece of silk or cotton poking out of the breast pocket in either border points; a puff style or plain straight fold, it completes a man's dress attire.
The pocket square has been part of men's wardrobe since the turn of the century. It's origin is the handkerchief, which we come to know for its sanitary use; wiping your brow, hands or blowing your nose. The pocket square came into it's own category years later. Men adopted to the silk square for it's novelty patterns of foulard's; dots and paisleys. This still holds true today with a vast amount of patterns from classic to whimsy. The fabrications from a stark white "Irish Linen"; silk and wool challis. The truly luxe can be made up in wool/cashmere; silk/cotton or silk/wool/linen. Whichever fabric suits your mood, the collaboration of pattern and colors is the final detail.
The classic tag line for the AMEX card was "never leave home without it", I would use the same line in your daily wardrobe. Never leave your jacket breast pocket naked. Always have the pocket square present in your jacket at all times. One sin you'll will not be repented for is matching your square and tie. Don't do it! Lastly, remember it's for showing, not blowing.