I thought the mushroom farming mechanic in the hexagon area was really interesting and it was important to place mushrooms carefully to maximize growth potential. But I didn't realize that when I first started playing, so I filled the entire area with mushrooms that wouldn't grow and I couldn't find any way to delete of the unwanted mushrooms.
Once I got to the next enlargement, it cleared and I could start planning properly, but I think those mistakes slowed my progression quite a bit. Would be nice to have a way to remove mushrooms, even if you lose the initial cost to plant them.