Re Dr John, 3/4 time is relatively rare bcos it's not a 'natural' dance rhythm. You've got 2 legs, hence a natural rhythm is something that involves both legs moving in sequence. 3/4 dances such as the waltz require that everyone learns how to do it, it's not something that comes naturally. But there is something 'natural' about groups of 3 notes, hence 3/4 time sounds nice, and hence the reason why lots of music uses 4/4 time with groups of triplets - blues is almost exclusively triplets.

The first note is actually played slightly louder - that's the emphasis, in the same way as you sing "hole" slightly louder in "There's a hole in my bucket". You may not notice that you're doing it, you'll just notice that there's emphasis on that syllable.

And re John in Brisbane, there's an apocryphal story about Charlie Watts which I like. Someone showed him a drum machine, and said "This machine can keep time more accurately than any human being." Charlie thought about this for a little while, then said "Nah, don't believe it".

Grab.