I have a headcannon that Pietro is afraid of going fast if he’s not in control.
Like if one of the Avengers is driving too fast he immediately clenches up and tells them to slow down.
One day they take him to an amusement park and as soon as the roller coaster speeds up for the first time he starts screaming, “I DID NOT SEE THIS COMING. I DID NOT SEE THIS COMING.”
Me *sees the Maximoff twins*:
Look at these beautiful MUTANT children of mutant MAGNETO and MAGDA being MUTANTS. Yep, definitely Lehnsherr spawn. Yup, just two MUTANT CHILDREN OF MAGNETO being MUTANT CHILDREN OF MAGNETO. Precious MUTANT children. Of MAGNETO.