I heard a story recently about someone who would ride the same loop on his bike on a regular basis. As hard as he could; and it always took him 43 minutes.

At some point he stopped wanting to ride the loop because just the thought of it brought the pain of all the hard work.

As an anecdote, he decided to go for the same ride, but rather than pushing he slowed down, enjoyed the scenery, and enjoyed himself much more.

He returned home in 45 minutes.

There is a place to push. Interval workouts will likely help you get faster. But sometimes it is also good to just enjoy ourselves. It still may have the same overall benefit; or maybe even more of a benefit.