Why didn’t the traditional armies in the colonial period ever attack from the side, instead of lining up face-to-face? Or think to duck when hearing the other general yelling “Fire”?

by BeansnRicearoni

Every time I watch movies like brave heart or The Patriot, it baffles my mind the way battles were fought. Were the traditions of the day , more important than winning the battle by any means necessary? The idea, had to have at least crossed their minds to attack from the side, or a different formation of angle of attack . Or order the soldiers to do up downs, when the other side is firing, to give better chance of survival

DanKensington

Because lining up in a tight formation is - and until the advent of smokeless powder, has always been - the means necessary to win the battle. I commend to your attention the appropriate section of the FAQ on Early Modern Warfare; you want everything under a heading that says 'linear tactics'. I recommend starting with u/tyn_peddler's answer here, and moving onto the rest.