Optimizing relationships in veterinary practice requires the development of mutual respect between the parties involved. An example of mutual respect would be scheduling an appointment when you desire to meet with someone and making sure that you arrive on time and finish your meeting before the stated deadline.
It is common in veterinary medicine for some pharmaceutical or distributor sales representatives to drop in to a practice unannounced or without an appointment. It is also common for veterinarians to schedule an appointment with someone (not a client) and then either cancel the appointment or show up very late.
In business, these behaviors are examples of disrespecting those you seek to meet with. If you respect others in business, it is important to respect them enough to schedule the appointment. If you don't want to meet, then don't schedule the appointment. However, if you schedule the appointment, be on time or early, and also, make sure that you complete the meeting prior to the stated end point. These behaviors convey to the other party that you respect their needs, that you have their best interests in mind, and you respect them enough to commit to and conduct the meeting as scheduled.
Failing to schedule the appointment or to be on time is a loud signal that you don't respect the other party enough to keep their interests in mind. Seek to develop mutual respect. It will serve you well.