As the title and highly-detailed and complex diagram indicate, GW2 has a wonderful way of making everything interconnected.
Dynamic events often take place in the same area as the quest hearts, with qualifying enemies often spawning with it or being the expected filler between the boss fight. The result is that you either kill two birds with one stone, or two kill birds with two stones, but the second one doesn't fly away and make it hard to hit it.
The daily achievements tend to include a large dose of killing in a particular zone or mob types, both of which are the inevitable results of hearts and orange circles.
I tend to like the champion trains, though in a sense they're all I know, since I wasn't around for the clearly better thing that happened before them (I've been there before, I know that change is always for the worse). They feed into the dailies, giving some of the trickier things such as veteran kills, and an abundance of junk to salvage.
While we're on the subject, I rather like the daily system. The gathering one is a natural part of any movement outside the cities. At least until I've finished my hearts the zone kills are a freebie. Salvaging flows from killing. That leaves two more, and those can be as easy as reviving player or NPCs or doing a couple events, both of which you're probably going to run across during hearts or gathering. There are WvW ones as well, but I've not yet needed them. Given the sometimes slow pace of WvW I can see how those could be tricky for someone who wants to hop in for a quick completion. Of course I dislike the aquatic slayer one because I get disoriented underwater, but I've never felt like I needed it, so I see no major problem.
Finally, there is a missing link in the diagram. Players eagerly work together on chained dynamic events. Maybe chains aren't trains, but they rhyme, and that's what really matters when you're drawing diagrams on a chalkboard.