Only the Japanese have found the perfect balance, from what I've experienced around the world. When you enter a smaller shop usually all the staff will do this greeting that basically means "welcome" but you don't have to respond to it. If it's a very tiny store with just one person you can say hello if you want. But then they'll leave you alone in most stores. However, the moment you need help you can just say "excuse me" and someone will rush over to you and help you out with whatever you need. If you need more time to just browse or think alone you can say thanks and they'll disappear.

In the larger stores like supermarkets where there are staff doing stuff in the aisles and in different spots, they'll often say that same greeting as they walk around past you and other customers. It's just like an audio cue that a staff is there around you and you can ask them for something if you need. There is zero expectation to reply back to them or acknowledge them. But it makes it that much easier to find a staff when you do need someone in a larger store because you can listen for it as well as look for their uniforms.

The level of customer service is next level too. A staff will never end an answer with "I don't know" or "I'm not sure." If they genuinely don't know they will find someone else who can answer it. If they're stocking an aisle and you ask where something is, they'll walk you over to the aisle where it is and help you find it, instead of just saying "check over there."

No offense to you Brits but customer service here is absolute dog water much of the time, but people seem to be fine with it usually? I remember once I wanted to pay for something so I walked up to the till and put my item on the counter. A staff was right next to me organising something on that same counter, and she took a whole 2-3 minutes to finish what she was doing before even acknowledging me and going behind the counter to ring up my thing. Blew my mind. I work behind a cafe counter here and I would never dream of doing that unless it was something I physically had to finish before attending to a customer, like having handfuls of cups that I was putting away. Even then I'd at least say something like "I'll be with you in a minute."