The job of a manager is to look out for the best interest of the artist. In doing so they also have the responsibility of handling all of the uncomfortable issues of business between the artists and the employees (musicians, merchandisers, promoters, etc.) such as money, accommodations, etc. Therefore you have to make sure you represent yourself well without coming out looking like a jerk.
Most managers, good or bad, are going to try to pull the wool over your eyes at one time or another. Not because they are necessarily evil or out to get you, but the nature of their job calls for them to execute certain moves that are contrary to your best interest. So right out of the gate, you are at a disadvantage.
I personally dislike talking about the uncomfortable issues of business with management because your intensions can be misconstrued, labeling you as a troublemaker or that you’re nitpicking. But it’s a catch 22 because if you don’t nip certain issues in the bud immediately, they can become huge issues later. For instance, I recently encountered a problem with management concerning the latest exorbitant airline baggage fees. The night before flying out to the gig, management sends me a text giving me a heads up about the fee change to expect when I get there, but offered no reimbursement. I responded by letting them know that I wasn’t absorbing any extra fees because unlike a background singer, I have to check my instrument. And for longer trips I need to check an extra bag as well, all being necessary to perform the job you hired me for, but I’m expected to incur the cost of doing business for you?
Needless to say, my receipts for “necessary” baggage, checked or carried, were reimbursed. So always be on guard. Choose your battles, but always keep in mind that their first initiative is to do what’s best the artist.