If you don’t mow your lawn i.e. the grass in many parts of the country, when you step out to play with the kids you might find you and your family stepping on some unwanted yard guests. You know, snakes, scorpions, certain smelly mammals all of whom like deep grass for cover.
Not to mention chiggers. I’m usually good at keeping up with grass mowing. One time years ago I got behind for some reason and the grass was pretty high. That was the only time I ever had a problem with chiggers.