I already mentioned this same thing in other posts, but well, today I stumbled upon another example of it.
Vim is like a unix commanline, lots of little commands you can combine one to each other. It has the cognitive style of linux command line
bufdo,argadd,argdo... These are the 'pipes' of vim. multiplicity enablers that add functionality,commands and power in an exponential way.
When writing ReST docs to take notes at university, I used Vim, and I got used to underline titles with an add-hoc sequence I made up (yank line,paste,visual line, replace, char) . Vim doesn't need a specific command for it, because it's immediate, and like most vim combos, it's like talking to it in a funny slang.
On the other corner, emacs: as part of emacs-goodies (ubuntu package with a bundle of emacs plugins) There's under.el. A plugin that exports 'underhat-region'. A function that underlines a region with caret characters. The bad thing of underhat-region is that it's not parametrizable, but that's not the point. The fscking point is that in emacs you end up stumbling upon functionalities that are already there as commands, but probably sunken among zillions of other commands.
I'm more a vim-style guy myself, but couldn't resist emacs+vimpulse combination. I think I'm sold.