Also, to answer your original thread title, when I first started training for triathlon I did it in a very unstructured way in the gym and would just hop on a bike/treadmill/cross-trainer; when I did that I found it painfully boring within about 5 mins and generally had to change which piece of equipment I was using within 15 minutes as I was so bored.
Since switching to structured workouts (e.g. 10 mins warm-up, 8 * 3mins hard + 3mins recovery, 10 mins cool down) the time goes much quicker - its alot more painful but I don't get bored!
I do occasionally just hop on Zwift and try and see how I do on their segment rankings (they have KOM/QOM rating boards for each of the big hills and sprint and lap positions), plus they've now mapped their 'worlds' enough that its reasonably entertaining to just explore and watch the scenery go by. Finally, I did my first Zwift race at the weekend and that really did hold my attention for the full hour of racing (set a 1 hour power PB too!)