It's one of life's small pleasures that on an almost daily basis I can watch people crash into doors. There are truly very few things more entertaining in the small town where I live, as sad as that may be. The best part is the majority of people don't even bother slowing down to read whether the door says pull or push, they just plow fruitlessly into the glass. If they're lucky, it will swing outwards. If they're not...well...
I almost pity them.
It's thanks to Encyclopedia Brown, the smart, cool kid who wielded his massive intellect in the face of kidnappers, murderers, and the neighbourhood bully, that I have never been counted among the legions that spend their time struggling to get through doors.
It was the crucial hint in one of the stories that a door will always swing in the direction of its hinges. Always. This simple fact has saved me from several potentially embarrassing incidents.
So in an ideal situation, approach the door slowly for maximum appraisal time. If there are blatant signs that say push or pull, then take your cue. If not, shoot a subtle glance along the frame for the existence of hinges. If you can see them, pull. If you can't, the hinges are on the other side, and you should push. Confidently step forward and open the door, impressing all who are in the general vicinity.
Thank you, Encyclopedia Brown