Default vendor colors on Unix system are horrid, near or beyond unreadable by default?dark blue on black, for example. Given the variety and number of computer systems I interact with, I disable color highlighting by default. A quick method is to use a terminal that lacks color support:
$ TERM=vt220 finch
As this spares the trouble of finding the application-specific color configuration knobs, for example /set colors off in irssi. Vendors such as RedHat pollute the default shell configuration with colorized ls; extirpate this by removing the /etc/profile.d/color* files.
vim tips includes configuration for turning off syntax highlighting and other annoyances some vendors enable by default.