May giving advice offend somebody in Germany? [closed]

"Gute Ratschläge geben" is often used somewhat tongue-in-cheek in German, in the sense of unhelpful advice or diverting someone's focus when that person really does not want to be diverted.

That said, it certainly depends on the situation and the way you put it. In a normal conversation, adding some "we always do XY, and it works really well" is not a problem at all.

P.S.

To expand on the appropriate tone, as a German I always though that Germans are quite straightforward, to the point of many being almost rude when using English and not really understanding the tone (friendly, demanding, angry) in a conversation with native English speakers. Your questions makes me wonder if Czech is really less polite than German in this respect.

But another important aspect is the relationship between the giver and the receiver of advice. Advice from strangers is indeed usually not so well-received in Germany, except when its helpfulness is really obvious. So if you tell your bus driver to go faster because he could make more tours per day this (hypothetical), he will regard you as somewhere between ignorant (P.P.S. or a Besserwisser) and a nuisance. But if your friend is an acknowledged expert in his field, people will probably take his advice reasonably well.

To soften the potential effect of rudeness you could always ask "may I give you an advice?" - and don't do that as a formality but really wait for an answer (probably nonverbal e.g. a nod) that indicates that your advice is welcome.
And of cause, as dunni already stated, don't say "You should do X..." but rather "If you do X, you can get more Y). Still the aspect of relationship should be taken into account, as pointed out by the previous answers.

I'm not a German, but a general thought on working with other people.

You might consider rewording the approach entirely. Instead of saying something like:

Instead of "x" try "y".

Or even

We do "Y" instead of "x", you should give it a try

Try something like:

I see you're doing "x", have you considered "y"?

You might even follow that up with a little more:

I see you're doing "x", have you considered "y"? We've found that it often works better that way.

This softens the approach, giving the "advice receiver" the opportunity to say "yes, we've considered that and rejected it because 'z'", or possibly, "No, we never thought of that, thanks!" or anything in between.

The second one offers that some supporting evidence while the use of the word "often" indicates that it's not an absolute. i.e. there may be times and reasons that even I wouldn't use the approach I'm suggesting.

Wow, this has really drifted off to Workplace or IPS territory!