I just got turned down for a job that I was perfectly qualified for to the point that I should have been a shoe-in for it.
Lately, it seems like being "perfectly qualified for the job" is the biggest turn-off employers have.
They're rather have someone underqualified so they can pay them less :/
Remeber it's not all about qualifications. There are a million different, mostly stupid, reasons an employer might turn you down especially if you have an interview. Everything from they didn't like your deoderant to they way you sat in the chair and combinations of everything in between can influence them. Those things are probably actually more important than qualifications in some ways. It might be something of a myth as I can't remember the source of this, but supposedly an interviewer will have already made up their mind as to whether or not they're going to hire you within the first 5 or 10 seconds of meeting you.
It's infuriatingly unfair but that's the way people are. Everyone, whether people like to admit it to themselves or not.
Now, remember though, some of those little nuances can tell a lot about a person's personality. Someone who slouches in their chair a lot or sits like they want to prop their feet up send possible signals of apathy or rebellion, something most companies aren't too well to desire. Body language is a very powerful thing, which is why a lot of "self-help" books pound in the whole "Look confident even if you aren't".
Smells, such as your example of deodorant, can also spell out possible issues. If you smell "different" than what is expected, this can be a signal of distance and attempting to stand out, breaking "work culture" as it were. On the other hand, smells also influence things like mood (as do colors), which is just a bitch.
Somewhat related:
Walmart for instance has a nice little weeding process when you apply. You go through a survey answering from strong disagree to strong agree. Now, while this might seem like an obvious personality test, it actually works differently than might be assumed. They actually give almost no fucks about what you answer as opposed to how you answer, they want people who put either full tilt agree or disagree since it signals confidence and snap decision making. This can be used to find possible leaders and most importantly, find people who will do as desired without question (Anyone who does rebel can simply be fired).