Instead of worrying about the Internet connection, better prepare for 230V AC electricity here... Or learning the critical sentences in German, for example "Ich möchte diesen Teppich nicht kaufen",
Bringing converters are a must for every international traveler.
I haven't taken German in some time, but isn that, "I'd like this rug without paying" Makes sense if you're soon to be talking to the police.
I would think the most important phrase anyone could know in Germany is:
"Wo is die Kneipen"