how to earn love of all germans with 1-2 sentences?

Nazi-jokes incoming ... :s

"Wenn ist das Nunstruck git und Slotermeyer? Ja! ... Beiherhund das Oder die Flipperwaldt gersput!"

It's a killer.

"Your beer is tolerable."

edit: which also may work is "your language sounds pretty nice", that's not something they hear often(or ever). Fact learned by life, not by memes and posters with "pen" & "kugelschreiber" example, I was learning Deutsch for 3 years.

Did you rebuild Drezno yet ?

Wurst in a beer!

How about you type something funny and translate it into German? Google German humor?

Supergeil

Warum ist die Banane krumm?

Weil sie einen großen Bogen um die DDR gemacht hat!

(This is an actual German joke.)

If you get the chance, throw in some physical comedy by imitating Mr. Bean.

German beer is better than Czech Beer.

(lie) shots fired

ACHTUNG!

ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!

DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN.

just yodel. works on austrians as well

Ja Hans, schneller, schneller! And: Das ist eine fantastische position!

Don't ask.

Disclaimer:

I have never learned German language in my entire life.

Danke und bitte. Or Schlampe and Scheisse.

Bück dich Fee, Wunsch ist Wunsch

its like: Bend over fairy Wish is Wish

Here's one. Germans are going love it cuz its funny.

Wie heisst der Chinesicher Sexminister?
"Schwing Dein Ding"
or
"Fu tzu-Eng"

Es ist mir Wurst!

"Ich esse gerne Weißwürste mit Sauerkraut."

At least people from Bavaria / Bayern will probably hate you for this sentence :).

Another very popular sentence: "Das Internet ist für uns alle Neuland."

"Schürrle setzt sich durch über links.... Mach ihn...... und er macht ihn... Mario Götze..." Every German will love you.

David Hasselhoff.

Just say "Maschendrahtzaun", ppl will love you.

"Do you know what Germans like to drink? Blood of Jews!".

I don't know about such sentences, but if you find one that works universally, please tell me, cause I'd like to know. In advance:
Especially americans tend to mix the german language up with english in such a vile, nonsensical and excruciatingly bad fashion, it becomes an intolerable gibberisch and it's not the least funny to hear someboy spout some would-be-funny stuff.
Second: Don't mention clichés like Jodeln, Oktoberfest, Lederhosen while we're at it, probably leave Kraut outta there, too and, for the love of god, leave Weißwurst (white sausages) and pretzels outta there too, because these things are all bavarian, not German. Mentioning those things in front of a bavarian will net you a bavarian complaining, how the international german image is pretty much a bavarian image - if you're really lucky, and I mean unlucky, you will have that Bavarian start complaining about how the Prussians (that's what Bavarians usually call the rest of the German population) are idiots. If you're going to have a Prussian in front of you and tell him about all the "funny" things about "German" culture, he will tell you it's all bavarian and it's gonna be like talking to a bavarian, just the other way around.
Just talk to people here, German humor is hard to grasp, but especially people under 30 tend to be very friendly and will likely talk to you over a beer (or five)
And please, whatever you do, for the love of god, don't drink anything else than bavarian (real) beer and NEVER EVER drink less than 0,5l out of one glass - unless you're ordering a Kölsch (don't) and a Schnitt (you may do that if you're really drunk already)

3german5me