When You Finally Understand a Concept… and Then the Next Problem Destroys You

Math textbooks be like: "Now that you've mastered this, here’s a slightly harder problem!" - proceeds to drop an unsolvable nightmare that looks like it was forged in the depths of Mordor. Meanwhile, physics students are out here plugging numbers into formulas like a cooking recipe. Where’s our easy mode?!

Upvote if math has personally victimized you.