I started as an SEO back in 1998 when Google was but a whisper. We were ranking sites by calling them A Best Service so we could rank alphabetically at the top of the Yahoo Directory, which was the #1 source of traffic. We would tweak an on-page factor, then watch in Infoseek and Excite as the site rose or dropped in the SERP's.
For the last 10 years or so I've focused on On-Page strategies, link building, and content marketing for a variety of businesses.
I enjoy SEO as it's always challenging, always interesting, always engaging.
Now with the evolution of SEO and the advent of social marketing it's a different game as it's not just about making artificial agents believe you are the best, now it's about convincing people too. It's made SEO a lot more interesting and creative!