I like a challenge as much as the next guy, but I don’t enjoy spending 30 minutes (or less!) in a story mission only to have it fail. Whether from when a sentry blows up, or too many enemies get to the core, or when people run out of lives trying to rez one another in the middle of a fight corridor, it’s not a good feeling.
If, instead of just stopping the mission outright, these sorts of failures resulted in a loss of points, or medal status, that would be fine with me, but just cutting my playtime short makes me not want to come back and give it another go, and I don’t think that’s Gearbox’s intent here. I want to get invested in this game, but I keep getting confronted with unwelcoming barriers to just enjoying my experience.