Jim Hamilton in his highly recommended commentary on Revelation (pages 381-382):
My friend Denny Burk had prayed a beautiful prayer during our wedding ceremony, and the morning after the wedding I sat at the kitchen tale, reading that prayer. Before long I was weeping. I think it was a kind of emotional catharsis. Before the wedding I was amazed that I might get to be Jill’s husband (I’m still amazed by it!), and I couldn’t wait for it to happen. Now I was overwhelmed that it had really come true.
To be honest, I wondered if there was anything else to look forward to in life. The best day of my life had come and gone. Was there anything left to long for in life? I was too short-sighted to see that life with Jill was going to be even better than our wedding day itself and there were all sorts of things to look forward to, from doing things together to having children to walking life’s pathways and enjoying each other’s company. Just being with her is a blessing unto itself.
Perhaps when you think about what will happen in the new heaven and new earth you wonder if there will be anything else to look forward to. Perhaps you wonder if all suspense, all the drama, all the tension will be gone. To think about the new earth as through there might not be sufficient contrast to make it interesting would be as foolish as a single man being worried that after the wedding day there is nothing left to which to look forward.
Boredom = inactivity over time OR
Boredom = multiple repetition of action over time.
No time = no boredom.
Rev. 21:23 marks the end of time as we know it, a wrap up of linear time which began at Gen.1:4 .