I always hope for interviews from my job applications, because I don't know how desperate I should be. What makes me hope for an interview from a particular job, and prompts me to assign my special asterisk of interest in my job search spreadsheet, varies. Sometimes it is the department website, which reveals interesting research or a particular dedication to teaching. Sometimes it's the college, which might have a music conservatory, a special summer research program, or an intriguing mini-term like I had in high school. And in one particular case, it's the letter of acknowledgment.
I have received seven e-mail or snail-mail notifications that my application has been received and will be reviewed, occasionally mentioning that my application will be complete when all of my letters of recommendation have been received. The snail-mail letters come with real signatures, but have otherwise been form letters, occasionally with checklists of what materials have been received. Until now. The most recent letter may have started life as a template, but it shows a certain attention to detail. The search chair didn't just say that they were missing one of my letters of reference, he had read my cover letter, specifically the part where I specified who would be sending my letters, and he specified whose letter had not been received. A very small thing, but something that makes the department look good, and makes me think I would enjoy working there.
And that college has received the final letter by now, making me hope I will hear from them again, soon.