Cook the pasta according to package directions. Drain and set aside*.
Heat oil and butter in a large skillet over medium heat until the butter is melted. Add the garlic and cook until fragrant, 1 minute.
Add the shrimp and salt and pepper, and cook until heated through, about 2 to 4 minutes. It should look pink and opaque, not grey and translucent.
Take off the heat and stir in the red pepper flakes, along with the lime juice. Add more salt and pepper, to taste. Add the pasta to the skillet, and stir in the chopped parsley. Toss to coat, and dinner is served!