Guild Wars 2

Are ridiculous. Invincibility, and an AoE knockback that you cannot block against.
What were you smoking when you thought this up? Just curious.

You can block the projectile before it explodes and knocks back everything.

Stability, reflects/projectile stoppers, the slow movement of the projectile allows you to jump to nearby platforms when they are coming for you.

They can be annoying at times I will admit, but it isn’t to difficult (and the fractal that needs the most polish is dredge rather than harpy).

The easiest way to do harpies is for the party to move as one, if you have a guardian, or an ele or a mesmer, you can block or reflect the attacks, and if the whole party moves as one, harpies die real quick, you can also skip the harpies

It’s not so bad if you do it right. Here is how you should do it http://www.youtube.com/watch?v=B-Q8YDPg0uQ