Eventually you'll find having to wipe out good space all around the bridge in particular just to get it to break ground losing good stuff in the process that doesn't even need removing. It will also want to destroy many squares around the area of where the bridge/tunnel hits the edge on both sides and it will consistently and obtusely bitch it won't build until it is right, even if it looks like it.
It will want to make sure all terrain is entirely even. In 3000 bridges and tunnels are handled the same way.
In 2000 you just went to the edge of water and it prompted you to build it, that's it. Try making a bridge or a tunnel and not get a growing urge to punch the screen.
