Idea:
$ at --remove-the-last-job-I-submitted #(of course also pick a one-letter
option for this)

You see often we regret submitting a job we just submitted, and want to
remove it and resubmit it. However, looking up the number is a little
too much trouble.

But should be used with caution, as it will eat up previously submitted
jobs with no way of getting them back.

When used by root it will only remove his jobs, not anybody's, so safe
in that aspect.