Music choice is KEY! Although I wouldn’t be able to stand to listen to 2 seconds of it when I’m not working out, I sometimes listen to techno? (not sure what they call it nowadays). Try creating a Paul Oakenfold Pandora station and see if it works for you. Some U2, Van Halen, and ACDC also works well for me.
Also, doing structured sets (e.g. 4 minutes steady @ 70 RPM (out of saddle for :30 @ 2 minutes), 1 easy…) instead of “ride 1 hour steady” makes it much easier.
Finally, some people like to watch TV while riding (e.g. team member Andre “the Conscience” likes to watch football while biking), but I find the workouts go faster and I enjoy them more if I “tune in” to the workout rather than trying to distract myself (however, I do like to have old Kona races on in the background).