One thing that amazes me from the German stand point is how pretty everyone tries to look. We even try to look "good" for our impression. A true 1944-1945 impression would have you in the worst quality uniform, almost no equipment and looking like hell. Yet we all go out trying to look like we are ready for a parade for the Chief of Staff.
I have done some things wrong out of haste, had it pointed out, was embarrassed about it, but learned. The trick is two fold - to listen to the advice and not take it personally - and second, when giving advice, don't be a jerk, try to be polite and explain why / what etc. Don't push it on them, treat them like a wild cat at your door step. Leave the information at the door in a bowl, if they want it they will take it, if you try to grab it and force it on them you are going to get your eyes clawed out.
Snickering about it to yourself then complaining about it on the internet is the lazy way out. I have no respect for a keyboard commando.
Robb