I tend to think along the same lines as Perna. I stopped attributing why Profs or anyone does what they do, just focus on the end result b/c there is no way of actually knowing what they think and we also have no power to change them even if we knew why. The only exception is to figure out the best way to reach them.

Squeaky wheel does get heard with professors in my experience, whether they like me or not, they will not ignore me. I'm here for an education and I have things to do to fulfill that. Half of their job is to help me to that. If I need an appointment or help with something, I will continue to f/u until that happens, be it email, phone call or in person, until it happens. That's true at school or in business as well.

The professors forget sometimes, being focused on their research, the students are the other half of their jobs. Some professors, like many others out there, are not always good at prioritizing and sorting through what comes their way. It's up to you to ask for and get what you need.

It would be nice if all took interest, were considerate, and were prompt in their replies, but at school and in business as well, this is typically not the case unfortunately. I remember this too when dealing with others so I treat others as I wish to be treated.

I would call or go find him to pin him down to set up the appointment if he's not responding to an email request. Just say, I hadn't heard back from you but that we need to meet, when is the best time for you this week? Never leave it open-ended, what times best for you? Could be 3 weeks or a month from now. Gives you what you need, puts pressure on him and a time is requirement. Will more than likely fit you in this week, but if does need to move it to next week, if that's ok, do not leave w/o a confirmed date.

Good luck!!