HELP I need help involving WW 1 for a social 20 essay, and i want opinions?

WWI had been so bloody and cost so many lives, nations had to mobilize more people for the war effort, or lose. Canada very much felt a part of the British Empire, and did it's part to the fullest. Was that justified? Does an individual have to give up some personal choice/freedom sometimes for a greater, common good...even to the extent of perhaps losing his/her life?