I very rarely run in shoes, always barefoot for 6 years. Running on grass / trail is what I do when my legs need a rest because it's easy on the legs. When I had shin splints I could only run on the grass. If I run a week on grass and then run on asphalt my easy pace feels so easy, running on grass is slower.
Running style changes on asphalt, my cadence is higher, feet hit the floor very stable, feels lighter and more fun. On grass it feels so soft and I love it when the grasscutter is out mowing the fields in his little tractor on a sunny summer morning, it's like running on a soft carpet.
When I wear shoes it's not as fun, feels like it's all cardio upstairs and my legs just feel slow/clumbsy.
The worst surface to run on is asphalt with minimal shoes 4mm, it kills your calves for 3 days.