What Happens if You Let Your Grass "Go To Seed"?

I ask this because I’m getting tired of cutting the damn lawn-it’s been rainy and sunny here, so the grass has been growing like crazy! If you were to allow the grass to reach a height where it would flower and put out seed, would you be harming your lawn? Just wondering!
As an aside-I once read that lawn grass was the biggest cash crop in the USA (in terms of money spent to grow the stuff)-what a deal-you spend all kinds of money to grow the stuff, then your big problem is how to get rid of the clippings!

If you let the grass go to seed, when you eventually cut it the lawn will look like tufts of grass and it will talk a lot of work, or re-seeding, to get it looking nice again.

There’s only one type of grass that should be let flower.