ARMA series, to the first Operation Flashpoint game (which got retconned into ARMA: Cold War Assault, making ARMA 1 a sequel to OFP). I have no idea how ARMA so completely missed the point of the game, from both gameplay and story perspectives.
I've never been in the military, so I don't really know what a siege or urban combat or anything looks like. But OFP's scenarios are plausible. In one mission you play a helicopter, supporting a ground attack on a town. You see armor moving against armor, then infantry coming in behind once you've taken care of the tanks. Whether or not that's what would really happen, it makes sense to a layman as being some kind of realistic.
In an early mission from ARMA 1, you have to blow up a bridge while an enemy convoy's passing over it. Fair enough, but your squad is way on the other side of town for no reason. The go-ahead to blow up the bridge comes after some vehicles are already over, too, so you have to run away from some really dangerous shit, totally unsupported. Then, while on the way to rendezvous with your squad, you have to blow up three APCs. Or maybe it was two APCs and a tank. Any of those will kill you instantly if they spot you, and you have to do it all by yourself. It doesn't make sense at all. It's not even like they consider it an inconvenience, it's like they're targets of opportunity you could easily deal with along the way.
Also, you have to swim to plant the bombs under the bridge. If you swim too long in ARMA 1, your backpack just vaporizes, taking your assault rifle and ammunition with it.
I have problems with ARMA 2 as well, but I didn't even get past the third real level (Razor Two).