23/4-SF2 as flat as a map

Despite ACC/CCA said it charges 16 dollar for the door-to-door shuttle from airport to the apartment, I guess a few dollars tips is inevitable, however the driver dared ask me if he could just take my 20 dollars bill.
I saw him giving back changes to at least three of the four other passengers. Maybe it is because he and I are both Chinese? But I must took the more expensive shuttle anyway, rather than with the BART then BUS then walk. For from the direction given, the five blocks from the campus to the apartment seemed to be uphill, so I dared not take the risk. It turned out my fear is correct, and its is a really steepy one too! I am always good at maps, but in a foreign city, with the shuttle driver getting lost and me who directed him to find the CCA, it seemed really a bit ridiculous. San Fran, as some guidebk said, is a city that built its grid system without regarding the up and down slopes, and so most of the time you can't tell them from the simplified map.