FEAR???? living with what soulless money grubbing beasts that they become when they hit puberty.
Now only two options exist. You can wait till they come of age and go into hiding with your Woot monkey collection. Or have them leave, only to return broke in 10 years with a spouse and 3 children.
Alternate woot reality !!! (Woot stops selling unaffordable Dyson things, and sells usb time machines for$16.99)

The loss of quiet. Never realized it until the kids went off to college. How sweet it is to be able to hear yourswelf think again.

Loss of freedom is significant, but my research indicates that near total loss of spousal nookie time (don't make me spell it out) is the hardest thing about being a parent.

Being a single parent...because dad decided he'd bale out & marry his ex-high school sweetheart. Our son was 12 years old at the time & heard it from the kids at school. Oh, & it didn't help that his dad was a pastor at the time.