The proper preparation for the coming Day of the Lord is service rather than speculation. Human beings are naturally curious, especially about the future. Add God to the mix, and it is easy to understand why speculation about the return of Jesus is so attractive and fascinating to so many people. But while it might seem like a harmless activity, there are several potential negative aspects associated with it. Since no one knows when Jesus will return, speculation about when he will return is largely a waste of time, time that could be better invested in more productive activities.

Source: Holmes, Michael W.. 1 and 2 Thessalonians: The NIV Application Commentary from Biblical Text to Contemporary Life . Zondervan Academic. Kindle Edition.