I was walking around the precinct of my work with a packet of paper hand towels in my hand today. One of the tenants (who I didn't know - but may have seen him around) called to me and asked if he could have the hand towels. I thought it was a bit rude (he being a stranger) but I gave them to him. I got a smile and a few pleasant words for my payment.
From his perspective he got something for nothing, and that it wouldn't bother me because I got access to the stores and costs me nothing. It did cost me 5 minutes of my time to replace the item, as well as corrupting myself by giving away the bosses stuff, - All for the sake of not being able to say "no".
In my job I come across lots of people who I feel I need to nod to them in passing sometimes, to acknowledge their existence. Generally I try to look at the ground in front of me as I walk. If I acknowledge somebody's existence, it leaves me open for people to ask me for stuff, or to fix their problems, like in the above example. My boss does not pay me to do that.