SC Freiburg vs Aston Villa

The referee gave a yellow card for this challenge, but it should have been a red card. The Aston Villa player used a high, scissor-kick motion with both feet off the ground to challenge for the ball, and even though he touched the ball first, the excessive force and height of the contact—especially near the touchline—endangered the opponent's safety. That kind of dangerous play deserves a straight red card, not a caution.