I just quicksave before asking for a job, and load if it's the wrong location. Bu i agree, i've never "finished" the Thieves Guild just because of that.
I cancelled the quests instead of reloading a save, so I have -17 in Thieves Guild quests.
Failing a quest gives you -1 in quests completeted? What a miss from Beth!
I thought it was stupid how that was the requirement for becoming Guild Leader. It wasn't even explained. And the way it worked was really bad. The Thieve's Guild quest line was great up to that point. The whole radiant quest deal is a total failure as far as I'm concerned. They are so repetitive that I never do any of them except that time where I was forced to if I wanted to be Guild leader.
Agree, it was awful to have to do 5 of these boring quests in each city before the real Guild Leader-requirement quests became available.
And to make it worse, it wasn't explained at all. I discovered it first after having read about it on UESP wiki.
Something else about the thieves guild that really grinds my gears, they all constantly gripe and complain about doing jobs to make them more coin, yet you're the ONLY member of the guild actually doing anything while they sit on their asses 24/7 in the flaggon doing nothing while ONE member of the guild does ALL the work.
I'd be okay with that if they had stopped after you become Guild Leader - but no, you still "better not make trouble", should know that "these jobs aren't going to finish themselves" and must be reminded that "it's one thing to say you've got the skills to be a thief - it's another to actually use them".