I would agree that the masses and computers trade off price but thats what your drawing your trendlines on price, your looking at price to see where guys will sell and buy and if you look with your head tilted a little trendlines are just angled support and resistance lines running with price, its all about price but I believe the lines help to see what price will be the area to make a good trade, the more times a price area is touched the more weight you have to give it as far as coincedence it happens to often to be coincedence but everybody trades their own way, it works for me