Just noticed your signature . Are you an ABBA fans ?
When in doubt:
http://i.imgur.com/XujHL.gif
Just nned to develop your ninja skills so no one can see you enter or leave the building.
I think the worst for me was 316 Central as if you go in at rush hour after work, most of the time there are people waiting for the bus standing right next to the entrance. What helped me get over it was realizing that most people wouldnt know what kind of place you are going into or what will you be doing in there anyway. Plus knowing whats gonna happen in the next hour helps
Her name is Sayuki Hanno.