Your experiences don't generalize to everyone. Just yesterday I drove home from an errand without navigation and discovered that the bridge across the lake was

Your experiences don't generalize to everyone. Just yesterday I drove home from an errand without navigation and discovered that the bridge across the lake was closed in one direction. This wasn't signed well at all and meant that I lost 10-15 minutes turning around and taking another route. Being able to have the car tell me when a turn is approaching rather than having to look at every street sign along the way wondering if this is my turn keeps me focused on the road and prevents the worries of "did I miss it?". It's strictly an improvement.