Did Jesus And The Early Christians Misdate The Second Coming?

I recently had a discussion on Facebook with a former professing Christian who argued that Jesus and the early Christians falsely predicted that Jesus' second coming would occur before the end of Jesus' generation. The discussion focused on whether the early opponents of Christianity reacted to the alleged false prophecy as we'd expect them to have reacted if there was such a false prediction. You can read the exchange here. You'll have to click on Comments in the lower right to see the comments section, then keep clicking on the relevant areas to see the entirety of the comments that follow.