By opening yourself up and making eye contact with all of the other patrons, you are also making yourself available to anything that comes your way, which could be a recommendation for a new book to read, a compliment about something you're wearing, or maybe even a date. Someone doesn't say hi back, and another person walks through the door ten seconds later.
You've lost nothing in the process, and potentially get to socialize in a lighthearted manner.
writing, archeology, model trains, or motorcycles), look for a community group that services other people with similar interests.
Your geographic location will determine whether or not there are readily accessible groups already ready and waiting for your membership.
If money is an issue, think about taking a class without getting credit or look into how old you have to be to receive free classes, since many universities now offer tuition-free options for seniors.