German's aren't rude if you're not rude to them. Here in the UK people won't be rude if you don't say 'please' for example, but some will try to kill you. So depends much on the person as well
I stayed in Munich for a few weeks some years ago, it is a beautiful city! Places you should totally visit are the BMW factory (quite amazing really), then get a beer here:
http://en.wikipedia.org/wiki/Hofbräuhaus_am_Platzl Nothing really beats the atmosphere of that place! Traditional huge mega awesome 'beer hall'. Dachau (a smaller town nearby) is known for the concentration camp, it was a quite gruesome experience to visit, but definitely worth the while.
Can't figure out anything more now, do ask if you have more questions