You call it paranoid. Most call it prepared. How do you know the "most good people" from the few bad when they enter your property? Once they enter the property and you determine they are not simply lost and are in fact bad people then it's too late to prepare.
Friend of mine was riding his motorcycle in a neighboring state. He carries in his saddle bags. Pulls into a nice, well lit, station and is filling up. Two very friendly, smiling, guys approach and start talking about his bike. His upgrades. How it rides, etc. He thinks these are two nice guys that don't need to be confronted. Until one says "I sure would like to ride that bike, how about it". My buddy says I don't loan my bike out. The guy says "It isn't a loan and I'm not asking". As they walk closer he pulls his gun from the saddlebag and points it straight at the two. They turn around, jump in the truck and haul ***.
What was at stake? Losing his bike? Getting beat up? Getting killed? - I have no idea and neither did he. He is a humble, easy to get along with guy who sees the good in most people and isn't paranoid. He isn't stupid either.
I'd call it paranoid if he confronted them for no other reason than wanting to discuss his bike. When they said they "wanted a ride and weren't asking", their intentions were known and it was time to be confrontational. Nothing paranoid about that.
Read what I said; "you should carry for the simple fact that if you need it, you likely don't have time to go get it"... That is being prepared.
My entire point is this: If you have a "reason" other than being prepared, you are paranoid. Too many things can happen in this world to set around and cite "reasons" for carrying. Once you start listing "reasons" beyond simply "being prepared", you are limiting your preparedness. Focusing on hypothetical reasons honestly does nobody any good at all. Each situation needs dealt with as best as possible, and a gun is always the last resort. There are no "silver bullet" solutions that fix-all...
If you carry so you can confront everyone that turns up your driveway or chase away anyone that speaks to you in public, you are paranoid and in my opinion; don't have any business with a firearm. The 'shoot first and ask questions later' mentality is a good way to make yourself known on the national news in a bad way.
Carry a firearm for the same reason you would carry a pocketknife, a flashlight, or an umbrella; simply "just in case". Chances are the situation you need it in will not be one you expect to need it in. The day you don't take your umbrella will be the day it unexpectedly rains, or the day you don't have a flashlight handy will be when the power goes out or you drop something in the dark.
No matter what situation you expect to happen, it will nearly always be the unexpected you need to be prepared for. Get on with living life and quit worrying about what might happen. Life is a wonderful thing and should be enjoyed, just be prepared.
Here's something quite valid for this thread from the "favorite quotes" thread:
"Those that go looking for trouble generally end up finding it..."