Krebs was easy. The pentose shunt pathway and (for me, others said it was easy :'() the urea cycle were nightmares. But I can still draw the phenylalanine -> epinephrine diagram!

The real krebs cycle: 1.) Need to know what the krebs cycle is 2.) Look up what the krebs cycle is 3.) Use the knowledge for what you needed it for 4.) Forget the krebs cycyle until you need it again

And it is even harder to remember and pronounce the full name