Couple of missions really irritate me on Challenge, notably the one where you have to save the satellite dishes. My build is towards Patience and refusal to stand toe-to-toe with huge armoured enemies, so I have to throw all that away and rush in to prevent twats with miniguns blowing away the sat dishes. Inevitable failure. Can we ditch the time trials? Don't mind how many enemies get thrown in - I'll find a way to beat them - but having to forego my entire play method gets me killed every time.
It's important to keep in mind that while your build and playstyle might struggle with some objective/mission formats, it likely excels at others where some players might struggle. The variety of minor and major goals can keep activities interesting and challenging - even if perhaps sometimes too challenging - for everyone.
As a counter to the satellite time-trial, what is a format that your build is better/best suited for?