Works wonders every single time… (London)

… saying “thank you” to people in their mother tongue.

    Rang my bank last night for some figures (bank interest for filing tax return — the annual phone call costs more than the interest I get...), and to get a replacement debit card.

    The debit card replacement lady had a strong accent, so I asked her at the end what her mother tongue was, thinking maybe Eastern European.

    Turned out to be Spanish, so I threw in a “muchas gracias”.  Instant delighted hoots from the other end of the line (and lots of Spanish thrown back at me after the “de nada”).

    Such a small effort, yet it produces so much joy in the recipient — every single time.

    She couldn’t even see that I’m Oriental looking, which would’ve reaped even greater results.

 

    I’ve seen it happen in person when they can see me and I say “thank you” in Bulgarian or Portuguese or Albanian.  An old Polish lady even asked me if I was from Poland!!

(London, 2025)

Universality

There's a Chinese phrase:  (archaic usage) 置喙 zhìhuì / "to-place beak" / "to stick one's beak into something" = to interfere / interrupt

Interestingly, the Italian phrase is exactly the same:  non metterci becco / "not put beak"!

Update, 311217:  My Italian friend Valerio says his Peruvian friend Ari says the Spanish have the same phrase:  meter el pico / "put the beak".

Maybe the link between the Italian and Spanish is the fact that they're both Romance languages.

Update 170218:
Spanish: no meter la nariz (also: el pico)  (Thanks to Ben Vickers)  
Catalan:  no ficar el nas  (Thanks to Ben Vickers)

Both "nariz" and "nas" mean "nose" (which is closer to the English version "to stick one's nose into something"), so the Romance language rule doesn't work here.

Romance | rə(ʊ)ˈmans, ˈrəʊmans | adjective: relating to or denoting the group of Indo-European languages descended from Latin, principally French, Spanish, Portuguese, Italian, Catalan, Occitan, and Romanian: the Romance languages. 

[mass noun] the Romance languages considered as a group. 

ORIGIN: Middle English (originally denoting the vernacular language of France as opposed to Latin): from Old French romanz, based on Latin Romanicus ‘Roman’.

Update 250619: 

Polish: nie wtykaj nosa w nie swoje sprawy / don’t put your nose into what’s not your business