If like me you're lazy and you don't want to compile the MySQL source to get it running on your Mac, you may have downloaded the package installer from the MySQL website.

I just spent the last hour or so trying to overcome an error that occurred whenever I tried to start the MySQL server:

Starting mysqld daemon with databases from /usr/local/mysql/data
STOPPING server from pid file /usr/local/mysql/data/mysql.pid
080205 mysqld ended

After digging through a few MySQL forum posts, the problem was related to permissions. MySQL files and directories need to be given ownership under the MySQL user account. The fix is quite simple:

cd /usr/local/mysql
sudo chown -R mysql data
sudo chgrp -R mysql .