I normally do not think about best and worst memories on a year by year basis, but went and looked through all of 2013's updates: it turns out that I have quite a few fond memories of that period!
The vaguest one might be dungeoneering: with the combat landscaped changed, dungeoneering was one of the few places where one could get by even when using momentum. It was during this period that I did a lot of dungeoneering and grew rather fond of the skill, despite hating it before.
Something that is a clearer memory related to 2013 is that there were quite a few quests. The main one that everybody remembers of course is the World Wakes, and I remember really enjoying that quest.
Wilderness warbands are sort of a double edged sword: I enjoyed how this activity gave rise to communities that tried to make the most out of it, but at the same time this minigame heavily devalued skills just for the sake of luring people as prey into the wilderness. Regardless, I do remember enjoying those times at which the wilderness would suddenly come to life.
And finally there are two updates which I enjoyed immensely: the world events. Though they were dragged out, I remember putting a lot of effort into getting all the rewards, mainly through skilling. I remember the fc that was used to tell people about sacred metal fragment nodes. Those weapon overrides I've gathered during this period are the ones I use to this day.
So yeah I can remember a surprisingly large amount of good things from this year. It might be that 2012 might be a better contender for my worst year, with the release of EOC and MTX (SoF), but probably there were highlights in that year as well.
"One should not mindlessly follow gods or the godless: