This 'setting them up, but not following through' scenario can happen to different degrees.The first is when a guy simply sees a girl around a few times and makes confident eye contact with her.Sometimes this nervousness shows up as the physical symptoms of anxiety.
Like they know how they want to act, but an invisible force field is preventing them from doing so.
This could mean feeling too anxious to start a conversation with an attractive stranger they've just noticed at a party. Some shy guys, especially younger ones, have had a crush on someone for years and years, and have never worked up the nerve to talk to her.
You're interested in a shy guy and having a hard time understanding him and coping with his shyness.
Remember shyness is a defense mechanism, it's not an unnatural thing or a flaw.
You just need to know the right way of getting to know them better and getting them out of their shell.