The Cool Story, Bro trophy in Borderlands 2 is story-related and can't be missed.
You will unlock the trophy once you complete the final story mission "The Talon of God".
*** Spoiler - click to reveal ***- Talk to Zed (Optional)
- Talk to Scooter (Optional)
- Talk to Tannis (Optional)
- Talk to Moxxi (Optional)
- Talk to Hammerlock (Optional)
- Talk to Marcus (Optional)
- Talk to Claptrap (eliminates optional objectives)
- Go to Eridium Blight
- Meet Claptrap
- Follow Claptrap
- Defend Claptrap
- Continue alone
- Find Jack
- Defeat the Warrior
- Call Moonshot
- Kill Handsome Jack (Let Lilith kill Jack)