what to do when u are full build? +PVE

What do you do when u are full build in PVE? alter and repeat? repeat the same raids over the time?

Well if you've geared up in full 277+, finished LK/Halion 25HC, go for some OS gear maybe. Make a role you haven't tried. Try different classes. Do PVP? When PVP gets boring go for twinking, achievement hunting, rare mobs, all cooking recipes maybe.
Old raids are nice to do from time to time.

Depends what class are you playing. Being full geared furry warrior or mage is a huge difference. Or even as a prot warrior where you can tank anything and soak tons of damage.

If you get full, do achievements, do pvp and farm gear for other spec,etc.

Make gold on AH

Help someone level to 80. :DDDDDDDDDDDDD

I usually pick another class/spec or start pvping at that point

Is your only goal in this game to get the bis gear pieces?