Awkward moments in shul are plenty, but I find the false handshake to be one of the most common and most awkward. The false handshake happens to all of us at one time or another, especially in shuls where you don’t know many of the people.
The false handshake is when you think someone is giving you their hand for shake when in reality they were reaching for someone else. In shul this is so awkward, because it always results in one of those half shakes and moves on quickly to the real person, with bewildered looks on both sides.
This happens to all people in different forms. A few weeks ago I was walking in Manhattan and I saw someone who looked exactly like a friend of mine, I tapped him on the back and started talking excitedly, I realized way after the normal amount of time that he was just staring at me like I was crazy. I apologized and walked away, very embarrassed shall we say.