It’s nothing but clear blue sky as far as you can see and the winds are light. Why get a weather briefing? I’m just going up for an hour! What could go wrong?
Have you done this before? Many people do, just to find out that they wish they didn’t! So what could go wrong? Let’s start by saying, just because there are calm winds on the surface, doesn’t mean it’s smooth and calm above. You may run into very strong turbulence. Winds above may be really strong too. Strong winds don’t always mean turbulence, but if you have little fuel and you’re planning a short trip somewhere and the winds are strong enough, you may not have enough fuel to get where you want to go. Winds can be very light at the surface and over 50kts just a couple thousand feet off the ground. What about windshear? An abrubt change in direction or speed of the wind close to the ground that is invisible to you until it’s too late. I’d rather know before I go!
There are also notams that can pop up. You decide you’re going to fly to another airport to visit a friend, to find out that the runway is closed for repair. Hopefully you’re paying attention and looking for the X on the end of the runway because if you land on a closed runway, you’re risking your safety, and now your license.
Oh yeah, let’s not forget the nice trip you were having, until you got intercepted by a military jet for flying into a restricted area due to the president being in town. That should be worth about a 90 day suspension of your pilot license along with a couple of thousand dollars trying to fight it! Think how much it would be if you relied on your income from a flying job you can no longer do for a long time.
The point I’m trying to make here, is that there are several things that could happen, even on a clear day. Isn’t it worth a 10 minute phone call to be sure everything is fine before you go? It’s better to be safe, than sorry.