1. Businesses that don't have a street number displayed, or have it so small/inconspicuous that you can't read it from the road
2. Businesses that don't have their actual name on the building or somewhere nearby
3. Businesses that have an address of 123 Main Street, but the (unmarked) entrance is actually around the corner on Broadway. OK, this one is probably out of the control of most businesses, they don't get to establish their own address, but it would be helpful to have a sign that says, 'Harry's House o' Bacon' with an arrow.
I spent 20 minutes tonight trying to find DS's workplace so I could pick him up. I had the street address, I had a navigator app that got me to the correct business park, and i had been there that afternoon. None of that helped me find his building after dark in a large business park that had no street lights, no numbers on the buildings, and no signs on the buildings. I finally had to park in a parking lot and flash my headlights so he could walk over to the car. I hate being lost anyway, but if I can see I can try to get my bearings. But it was just black, with big black buildings, and I couldn't even read the street signs because there are no street lights in the park.