I don't think he should get the job.
Meaning: Somebody else thinks he should get the job.
I don't think he should get the job.
Meaning: It's not true that I think he should get the job.
I don't think he should get that job.
Meaning: That's not really what I mean.
OR I'm not sure he get that job.
I don't think he should get that job.
Meaning: Somebody else should get that job.
I don't think he should get that job.
Meaning: In my opinion it's wrong that he's going to get that job.
I don't think he should get that job.
Meaning: He should have to earn (be worthy of, work hard for) that job.
I don't think he should get that job.
Meaning: He should get another job.
I don't think he should get that job.
Meaning: Maybe he should get something else instead.