The game has a ton of things to do if you're not a stick in the mud.

I've got 2 50s, working on a third (WAR).

Just got my first Relic last night (Veil).

Still gearing my SMN and SCH out. Missing 5 pieces of DL that I want and still need the entire Myth set for SCH and also myth hands for SMN. Then start pre-buying DL WAR gear. That's just me. I've played an average of 4 hours a day since launch.

A few things to do for fun:

Don't do more than 2 or 3 AK/WP runs a night. Prevents burnout while still getting you a decent tome count and capping myth each week.

Remember that other dungeons still exist. i run the low level dungeons a few times a week just for fun. Steel Vigil and Brayflox especially. You get to teach newer players, pick up gear that gives you an excuse to level other jobs, and some of the bosses are downright fun. I love tanking Aiatar as WAR.

HM Primals are fun. You can lot weapons for other jobs later on (if they aren't called) and the fights are enjoyable. Except Titan, who sucks always but its still great practice.

Shout to form FATE groups to go to unpopular areas. Its great seeing some of the fights that the normal herd FATE players will never see. Ever done FATEs at 48 past the Tidegates? Sharknado!

Explore and see the sights. Some of the zones in the game are breathtaking, and I collect screencaps of the scenery.

Hell I dont even do crafting, but there's that.

The game has a ton of stuff to do. The problem is that people only pick 2 or 3 of all those things, say "I'm only going to do these, and do them over and over!" and wonder how they get tired of it. MMORPGs are about experiencing a world, not just grinding aimlessly for one point of a stat.