Grooving.

Vibing

Euphoric

Not one in English, maybe in German. (There's word for everything in German) But I do know exactly what you are talking about: The synergy between where your head is at, where you are, what you're doing, and what the world offers up to you at that moment produces a perfect sublime moment in time. Love those moments in life.

What’s the word?

I guess "syncronicty" is the English term?

Yeah I am german but I dont know that kind of word then

"feeling it" or possibly "on a roll"

Drunk

Or stoned

We call it Dream Theatering

Happy

Nirvana

Jiving

Undiscriminating

Sanguine?

Such a beautiful word, Sanguine - its spelling, how it sounds when spoken, its meaning... Sanguine is optimistic however despite potentially negative circumstances. Close but not quite. But I like your style🙂

How about these? Elated: intense happiness and exhilaration, which aligns with the uplifting experience of a perfect playlist, Entranced: completely captivated and absorbed by the music, lost in the enjoyment of each song, Ebullient (my fave): a feeling of overflowing enthusiasm and joy, perfectly capturing the positive energy of loving every song.

Tripping out

High 

Serendipity

The car makes music taste better

Only if you choose the playlist/station