I didn't even make it to 18! 16 and I was out. Now me and hubby have a neighbor on one side whose 23 year old and 30 year old sons still live at home, the other side has a 24 year old daughter at home, and across the street there's a 38 year old man living with his father. They all think we're the crazy ones! We're both 30, two small kids, owners of our own house and no extra family members living with us.
My older sister still lives with my parents, and she's 26. She stayed living with them while she finished school to save money. My sister and I got kicked out at the ages of 18 and 21, respectively. My brother moved out when he was 19 because he got married. There doesn't really seem to be a trend with us...my mother-in-law would be very interested to hear about your neighbors, though, Trish, because she always talks about how she doesn't know what she would do if my husband and I had to move back in with her. Apparently she would want to let us because she wants to be supportive, but she's worried that we'll end up staying until we're like 40... It's kind of entertaining to hear how much thought she puts into a "what if" scenario that will most likely never happen. /rambling
My parents were convinced one of their four sons would go to prison or die of a drug overdose, they just weren't sure which one. We're all out of they house now and two of us are married, but I think they're still pretty sure it's gonna happen anyway.