Forth is very good in this regard, because the word names are short and there is no "fluff" around the syntax if you can even call it syntax.
Also there is no need to name your data. Literal numbers can be used just as easily even for memory addresses.
The "no safety net" means that Forth is a low level language. You can touch anything in the machine. Many times it is used without an O/S. So if you push a random number onto the hardware stack you will get burned.
Of course not. I was merely expressing that Forth makes interactively very easy.
And like all languages, it is impossible to evaluate them if you don't use them for some significant amount of time.
However there is no safety net. ;-)