If you issued a RENUMBER command with sufficiently nonsensical parameters (you gave it, I think, the first line number and the increment), the result was the error message "Silly.", which was (1) unusually casual-sounding and (2) not mentioned anywhere in the manuals. I can still remember the brief flash of OMG-it's-alive panic that hit me when my computer first told me I was silly.

If I recall correctly, RENUMBER only renumbered lines, but not the GOTO and GOSUB labels, so it was pretty useless after all :)

The best thing you could do was to stick to the practice of labeling by multiples of ten, and if you needed to hack something, you could still do it in one or two lines.

But basically programming in BASIC was hacking :)