Sure those things happen and we tend to hear about the things that go bad in the news and not so much about the things that go right.
WWI was essentially a mess because of changes in technology. Barbed wire, machine guns, and tanks to be specific. These three things essentially forced a change in tactics which not one military was really prepared to deal with, so yes, you had some very bad decision making going on that led to the trench warfare quagmire that developed.
Can you give me a specific instance in which soldiers have been given lawful orders to fire on peaceful citizens? In fact, all Soldiers under the Geneva Convention are bound to disobey such unlawful orders under severe penalty.
Have you ever been in the Military? You don't seem to understand Military Law and the Geneva Convention. It is important to understand these things.
Are there breakdowns in the system? yes of course, Abu Ghrab is a good example.
Do we all military and civilian have to obey "orders" and laws that we don't agree with? Yes. I don't like paying taxes to a State I am not even living in. I don't like the speed limits on some of the roads I drive on. I don't like the way my Grocery Store ques lines. I don't like many of the decisons my elected officials make. I see very little difference really in the rights and responsibilities that ANY citizen has in most of the free world.
I think a whole TV Series as done on bosses that make stupid decisions...what is that show? Office. How is this any different than the dumb decisions that a Military leader makes over a civilian boss? Sure the consequences may be different and stakes may be higher in many instances, but non of us are really above having to listen to the stupid rules that someone imposes on us that has power over us.
Granted, no military experience. Also I see you are of the military and a bit apt to therefore overdefend as I may be a bit apt to speak about something I'm not actually a part of. But I think we've kept it quite clean.
Asking for specific instances seems a bit odd seeing what's going on in the middle east and arab countries with peaceful protests.
As I said, idiotic control freaks in charge in that system leads to such orders and soldiers scared not to obey. Just fact. Not put down of you. No trying to link you into that. I think you'll find oppression by militaristic governments fits the bill nicely and in such cases what geneva convention? But alas we stray from help.
Military in the right way can help of course. There you are, nicely back on topic.