First learn this. Learn that every person comes into your career for a reason. That co-worker you kinda can't stand. That creative director who is uber-ridiculously-detail-obsessed. That sweet receptionist who offered you a glass of water while you were waiting.
It's no accident that particular person crossed your path at that exact moment in time. Now your job is to treat them with respect (even if it is merely respecting their ability to be a jerk) and respond always with professionalism and kindness. Your are building bridges early on in your career, it's much too early to tear any down.
Next believe this. Believe that any encounter with someone teaches you something. That ucky co-worker teaches you how to interact with difficult people. That polite receptionist teaches you that courtesy is title neutral.
Believe that you are going to spend your entire career meeting and mixing people who'll range from sweet as pie to big fat ugh. They teach you how to be a better person, a better creative, a better manager, a better whatever. You don't learn all this work stuff on your own. You learn it by having experiences (the harder, the better) with others. Those experiences are what help you grow in your career.
Lastly, act on this. Act like the person you've crossed paths with will be back in your life 10 years later. Because, in this industry, that's a given. Act like you would if, in 10 years, this person will be your boss. Or your HR director. Or your partner. I guarantee if you use this mentality, you'll always come out ahead.
Everyone remembers kindness and respect. Just don't ever, ever, ever forget that people remember disrespect and bad encounters even longer.