Tall, scary, loud people aren't always tall, scary and loud.
Perhaps you had a chemistry teacher like mine who walked into 10th grade with an 80-page syllabus, barking out all kinds of regulations, such as, "If you don't turn your paper in on the day it's due, it doesn't exist!" or "Chewing gum gets you two weeks in after-school study hall!" There were reasons behind her approach. For one, fear can be an effective motivator. But I only understood all those reasons later—much later. At the time she was merely a scary, loud, tall person standing at the front of the room.
At the end of 10th grade, after when we had turned in our papers on time and not chewed any gum, she threw us a party. By party, I mean a liter of Coke and a bag of Hershey's Kisses. Then she patted us all on our backs—awkwardly—and told us how proud she was of our performance. We were teenagers, and thus stunned. We couldn't believe there was a human being inside there. But there is always a human in there, even with rigid, terrifying bosses at work—and eventually, that human comes out. That human may not give you a huge, all-cash raise and buy you Jell-O shots every Friday. But she may leave you an anonymous latte on your desk on the day your boyfriend dumps you or praise you for nailing the presentation (in her office with the door closed so that nobody can hear). Now that you're an adult, your job is to know this will happen one day, and be less freaked out by the tall, scary, loud people. Once you do an excellent job for them, they will soften. Understanding this will make your life—and theirs—more, well, human.