Judgment comes while people are busy living as if it never will.
The people in Noah's day went on eating, drinking, and marrying. They knew not until the flood came.
Matthew 24:38-39 (KJV): For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark, And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be.
When the flood came, everything outside the ark was gone.
Genesis 7:23 (KJV): And every living substance was destroyed which was upon the face of the ground, both man, and cattle, and the creeping things, and the fowl of the heaven; and they were destroyed from the earth: and Noah only remained alive, and they that were with him in the ark.
Jesus said His coming will be the same way. Be ready.
Matthew 24:44 (KJV): Therefore be ye also ready: for in such an hour as ye think not the Son of man cometh.