Started with UNIX with Interactive UNIX and a UNIX variant on CETIA workstations as a high school graduate in 1990. I've used BSD 4.3 Tahoe, Reno, 4.4, SunOS, ULTRIX, OSF/1, Solaris, NetBSD, Linux of various flavors since 1995 (Slackware, Debian, Red Hat, Ubuntu), and OpenBSD starting with 2.8 or 2.9.
I've watched a lot of UNIX/Linux/BSD evolution, and enjoy helping folks get acquainted with the parts of the systems that many have forgotten.
I'm big into OpenBSD, and prefer using it in many situations. I love PF.