People will sign praise your work, tell you how much they depend on it, and how it changed their lives. Others will ask you tricky questions that really ought to be asked to a lawyer.
...and they still won't donate a cent. I get about 70 cents per thousand unique visitors. About one in every 14,000 visitors donate. Affiliate income is roughly 100 times that without trying.
Let me put it differently: with the same traffic, donations barely cover my groceries, and affiliate income is a comfortable salary.
I'm at peace with that. I make free things for a reason. It's just something to keep in mind when suggesting donations as a business model. Doubly so as an alternative to ads.
Another tidbit: praise people who create the things you use. It feels so good to know that people use and love the fruits of your labour. I've become lavish in my praise after experience the effects of it.