As the person sitting there - it is frustrating to have the "avoiders" ignore us and take the tissue themselves - we are there for a reason, we are paid to give you that piece of tissue. It takes nothing to give a smile and thank you.
As I mentioned, myself and my co-worker do not expect any tips. Tips come at the sole discretion of the customer, and there are far more non tippers than tippers. I am friendly by nature, I am stuck in that room for about 5 hours solid, I look forward to friendly people who come in, take the tissue and acknowledge the fact that there is in fact a person sitting there. A quick "how's the weather" makes the hours go significantly quicker.. and in fact I tell my friendly regulars NOT to give me anything - I enjoy the fact that they make the time for me, and treat me with respect, much more than the €2 they are going to throw my way.
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.