And it should be noted that Berlin is ridiculed in Germany for its horribly broken S-Bahn service. A few years ago, the Federal Railway Authority had to lay up about 3/4 of their trains because they were vastly underserviced. The operator then truncated many of the lines to have enough rolling stock available for servicing the remaining parts. These changes persist until today. (For example, I remember when the S3 used to run until Westkreuz.)

Unless you're trying to go somewhere important like say TXL airport. Sorry! That'll take an hour since you have to go train to train to bus!

TXL is a really quick bus trip from Jakob-Kaiser-Platz (U7). It's SXF where the bus takes forever.

Eventually this will be solved when the new airport opens along with its own S-Bahn station. Any year now...

SXF also has it's own S-Bahn station.