Second: Tough to say, probably nothing if that's the end of the communication. I hear stories pretty regularly of men being misled into taking someone out on the first date, paying for it, and then finding out a second date or anything beyond that was never on the table for one reason or another. It's definitely rude and vulgar, and people should reserve that for special cases.
Overall, I think people are bitter that dating has such a low probability chance in providing the outcome they desire. But you have to know that going in; "you look good in these 3 pictures and I liked your witty quote" is not necessarily going to lead to a lifetime of happiness. You probably have to expect 1000 failures for every success. But you only need one success.