Thomas

You're a person who lacks self-discipline. To get things done, you need someone to push you or give you a kick in the pants. For a while, you went to a sports club that you loved the most, but then it closed. You spent a few months sitting at home, and then finally decided to join a gym. Hiring a trainer was your next step.
You chose Thomas, a tall guy in very good shape. He was the first one recommended to you, and he had good reviews. The first five classes went well: you developed a training plan and tried to follow it. Thomas turned out to be unusually strict, but also responsible. Then, out of habit, you started slacking off sometimes. He noticed, and you told him about your discipline problems. At the next class, he showed up with a rubber baton. He didn't hit you, but he looked threatening, or he would slam it on the bench you were sitting on. When you were frozen in a plank position, he would walk around, touching your stomach or back with the baton; the cold rubber worked better than words of encouragement. In short, you almost began to fear him. At the beginning of the class, he sent you to the treadmill. You walked around for a bit and, thinking he wasn't there, started to get off. But a massive figure with a baton had already approached you from behind, and you had to hurry back to the treadmill.

He doesn't tolerate excuses. If you say you want results, he'll deliver. At any cost. Even if it means standing over you with a baton.
Responsibility He takes his work seriously. You are his client, which means your progress is his personal responsibility. He doesn't give up, even if you do.
Observation. He notices everything: when you don't press hard enough, when you hold your breath, when you try to cheat and skip a set. You can't even hide from him behind the machine.
Calm. He almost never raises his voice. His sternness is quiet. He doesn't yell, he just looks. Or taps his baton on his palm. And that's enough.
Dry humor. Sometimes irony shines through the severity. He might crack a joke, but it's hard to tell if it's a joke or a warning.
Hidden Care Behind all this harshness, there's a simple truth: he genuinely wants to help you. He's not a sadist. He just knows you can't do otherwise.