Losing faith in 'being polite'

My first time in a dorm, with other poeple from various countries and backgrounds...so far so good; so i thought! (they're lovely, though). So we're six of us in the dorm and share a hallway and a kitchen...thankfully, each of us have our own rooms, having very thin walls doesnt help the cause though...but i'm not complaining.

The area of my concern is the main door to our flat. The problem occurs when someone enters or leaves the flat. It's one of those things that in various scenarios will make you go so:

1) If you're sleeping, and the door closes, it'll make you get up with a frightening fit

2) You're writing away furiously into your book/paper; either a love note, or a hate note or penning down thoughts for an upcoming assignment...the unexpected occurs and the next thing you know, your pen's been flung to the farthest end of the flat OR the next time you're cleaning the top shelves, you find a bunch of them there, not knowing how they got there in the first place

3) You're using your laptop doing an eletronic version of the things listed in point 2 and then the door shuts and you furiously look at the room door, then when you look back into the screen, it looks something like this...'jhfoiy ure0u reu yth;ioftbru yrj mbrp yureu pfj hlyib0-E P'

So i decide that it's high time for me to do something about this...For most of the people who know me very well, they can vouch for the fact that i can be a stickler when it comes to being polite...yes, so i hate telling things as they are, being blunt etc etc...and try and be the 'nice'person (well most of the time) and avoid unpleasantness.

I casually mention something about this to a flatmate who vigourously nods her head, (she and one more fellow roomie to share my sentiment about the door), when we hear the darned 'S-H-U-D-O-O-M ', leaving a thundering after effect!

And then i say to myself,enough is enough, storm into my room and make a poster that reads, (politely, mind you), 'please shut the main door gently', go to the common area to pin it up on the message board...only to hear a 'S-H-U-D-O-O-M ' after a couple of hours!

So then, as if to defy the laws of the hall office, i scribble over the Important Notices put up by the hall manager on the darn main door itself, thinking ok, now everyone WILL have to read the damn 'plead' now, get back into my room thinking this has to work and guess what happened next................