[BvS]

You'll be able to have a great time for sure but there will be still some locals you will have a hard time to interact with, some jokes you won't get, some shows which will make no sense to you etc. Nothing to worry about but it still can make a difference to know at least a little German.

[dualogy]

Well, being a native German speaker I still suffer from all of the above issues with "some locals" on a routine basis...

But yeah, true, sure, knowing languages is always useful and can make a difference :)