What I would like to see REMOVE/LAST do.

remove-last.r3

Rebol []

; see - http://stackoverflow.com/questions/18231434/in-a-series-what-is-the-best-way-of-removing-the-last-element

remove-last: func [
    "Removes value(s) from tail of a series."
    series [series! port! bitset! none!]
    /part range [number!] "Removes to a given length."
 ][
    either part [take/last/part series range] [take/last series]
    series
]

some-examples.r3

Rebol []

do %remove-last.r3

b: [a b c d e f g]
remove-last b ;== [a b c d e f], 'g removed, no change to head
remove-last/part b 2 ;== [a b c d], 'e and 'f removed

b: [a b c d e f g]
append remove-last b 'x  ;== [a b c d e f x]

; also
b: [a b c d e f g]
c: append remove-last copy at b 3 'x  ; no change to b... c: [c d e f x]

; issues
append remove-last at b 4 'z  ; AT is superflorous here... confusing? maybe??  or just someone doing something stupid???