For me it’s easily refining liquid morkite. It takes forever. I swear half the team is off staring at a wall while you get the pipes built. Lastly, I can’t quite out my finger on it, but the refining portion feels so scripted and boring…Every other mission type is a blast.
I find Egg Hunt to be okay if I’m playing Driller or Scout, the guys with the best transversal tools to get to the more weirdly placed eggs. I don’t play it on Gunner or Engy though, it can be pretty bad (especially playing with Drillers or Scouts who like to set off the eggs as fast as possible with no pausing in between).