I like the semantics you type in the google search bar when using it for impromptu calculations. You can use ^ to raise to a power, for example. Just type sin 45. It’s all least surprise.

I wonder how many people use REPL of a language of choice as a calculator as I do.

I love how it works with units too, eg. c/433MHz or 4 bytes * 20hz * 24 hours

Syntactically it probably has a ceiling, to be so casual. Least surprise won’t work for very complex programs. But maybe the programs wouldn’t be so complex if you didn’t have to stick together complex program syntax either.