BERLIN, March 18 (Xinhua) -- Amid an overlooked handshake request and Trump's little appreciated "wiretapping" joke, German Chancellor Angela Merkel had her first face-to-face meeting with the U.S. president in Washington on Friday.

Although the cool-headed German leader attempted to sidestep Berlin's differences with its longtime cross-Atlantic ally, their sharp contrasts on defense, trade and refugees make it really hard to tune back an already off-key German-U.S duet.

Modified from declaring NATO "obsolete," Trump reiterated his accusation of Washington's European allies for not paying "their fair share" for the alliance during a joint press conference capping Merkel's visit.

Merkel, claiming that Germany is "going to work again and again on this", also said before her visit that the fate of the Europeans should be held within their own hands.

Free trade is another thorny issue where the two sides share little common ground. Trump, discharging himself as an "isolationist," stuck to the claim that free trade has led his country to accumulate deficits, while Merkel, as the head of the Europe's biggest economy, expected to reopen talks on an EU-U.S. free trade agreement.

After Trump took office, negotiations about the Transatlantic Trade and Investment Partnership, which Merkel and former U.S. President Barack Obama supported strongly, was quickly put to a stop. Trump also threatened to charge a 35 percent tariff on cars manufactured outside the United States from German brands Volkswagen and BMW.

On the topic of values like human rights, Trump and Merkel also have variance. Trump, vowing to put citizens' safety first, ordered controversial travel bans against refugees and Muslim immigrants, much in contrary to Merkel's welcoming stance toward refugees, which Trump had once ripped into for "ruining" Germany.

For decades, Berlin has been Washington's closest European partner, with Merkel sharing a strong bond with Obama. Their bilateral ties were also described by Merkel as the "bedrock" for German diplomacy.

But now the duet has gone off-key and the two countries seem to be facing increasingly unbridgeable gaps with a new U.S. leader and showed little rapport in their first meeting.

"Talk to each other instead of talking about each other." That's Merkel's motto.