Here's an easy way to make the func_door(s) open the way you want, and trigger_push(es) to push the way you want.
No more trial and error.
To start, Place an info_player_terrorist(any type of info_player should work also) next to your door or trigger_push.
Then... Double click on the info_player_terrorist and open the "Object Properties" window.
Click on the "Pitch Yaw Roll (Y Z X)" in the window.
Now edit the "Angle" at the black circle (see below) with your mouse or type in an angle.
Then read step 4 & 5 Mess around with the angle, but as you do this, keep an eye on the info_player entity.
Watch the direction in which it moves, and once it is positioned (face pointing in the direction you'd like) take the angle and apply it to your "func_door" or "trigger_push" Pitch Yaw Roll (Y Z X) in the same location!
Now, you've just positioned your "trigger_push" or/and "func_door" to push/open in the correct direction!
Uhh, when you look at the top view in Hammer, it's the same direction as the little white line is pointing in... isn't it easier to just drag the white line to whatever direction you want it pointed in?