As issues arise, please remember that you are not the only person/project with whom they are dealing. There are many projects, and many personalities. While you may think yourself reasonable, you may project a tone or attitude which does not engender an eagerness to assist. Whereas, if you are pleasant, reasonable and patient in your dealings - if you listen in addition to simply speaking, you will be more likely to find a sympathetic ear.
I encourage you to treat others as you yourself would like to be treated. I encourage you to give others the same benefit of the doubt that you yourself would like to receive. I encourage you to step back, gain some perspective and then move forward appropriately and with courtesy.
Remember eye contact, a simple smile and a lightness of tone combine to become a powerful communications tool that will serve you well in all your dealings for years to come.