Just a few reasons I can think of:
-Networking opportunitites. Getting a job not only in pharmacy, but in most other fields as well, is more about who you know then what you know. Confrences are great ways to meet potential employeers all over the country. A lot of large confrences (such as the APhA confrence) will have an exhibition area where companies have the opportunity to share about their company, and their products and services. Introducing yourself to other professionals is a great way to start making contacts, even if you're just beginning pharmacy school. Most pharmacists I have met are very excited to meet students and love being able to pass on words of wisdom and help students out when they can.
-Learning about the pharmacy profession. A large confrence, such as APhA represents many different areas of pharmacy, and it's a great way to explore different areas that you may have not considered or have had exposure to. You'll want to start thinking about what aspect of pharmacy you want to persue even before you start your APPEs. The role of the pharmacist is expanding, and there are a number of novel niches which you can apply your PharmD degree.
-Continuing Education. As a pharmacist, your education doesn't mearly stop when you graduate from pharmacy school- you will need to be keeping up to date with the rapidly changing field. Confrences typically have professional development seminars, and continuing education programs, and while getting the CE credits isn't going to be beneficial to you, since you don't have your pharmacist license yet, the knowledge you gain is valuable, and can be great way to tie what you learn in the classroom to the profession.
-Fun. Confrences have various social events and meet and greets. It's a great way to get to bond with fellow students, both inside and outside of your school, and other professionals.
As to the personality of the pharmacist, clearly you haven't met that many pharmacists, as personalities run the gamut. The profession is very diverse, so you are going to meet people of all types, which is fantastic!
