I don't work for DB, thanks for asking ;-)

I just did a quick vote with my coworkers who travel by S-Bahn/train every day: Out of all their trips they take one got cancelled or was late this and last week. That's for ten people and using it every day.

I have the feeling you almost never use S-Bahn and think because you had bad luck with the few trips you do all of S-Bahn must always be late/broken.

edit: Full disclosure, there seems to be a breakdown in service (because of a problem in the tunnel) right now.