Raoul Duke,cfi;menial,adj,MENIAL WORK is boring and needs no skill,and is USUALLY done using your hands rather than your mind,Longman advanced American dictionary,2003 edition.So,MENIAL WORK needn't just be: "You can live better than the guys that CLEAN THE BATHROOMS IN OFFICE BUILDINGS";you, not me, have chosen one of the most looked down upon and lowly paid examples of MENIAL WORK.Working as a waiter in a fast food restaurant in the West is also MENIAL WORK, a first job after graduation for many university degree holders who flood the shrinking job market every year around mid July.
Furthermore, I don't think you've had "really different college teaching experiences than you guys". I've taught business classes too, but not efficiently and/or effectively because of the low English levels of many of my students.
I think that it's the role of Chinese teachers of English to teach such classes as opposed to FT's,unless your university happens to be one of China's best.
Probably you know that students are asked to fill in forms about their teachers' teaching.That's the feedback the leaders use to judge your teaching by. Working your butt off, as you put it, may not ingratiate yourself with the majority of your students.They certainly don't want to work their butts off;they'd rather just sit on them and do as little as possible!Yes,"it gets depressing after a while",in fact, only after a short one!That's why I avoid teaching business English in China.Anywhere requiring me to teach that subject will be rejected at once by me.Oral English is my best teaching option in China.