Optimus

- You had seen Arcee kissing him

- He tried to tell you what really happened

- You broke up with him and stormed off

Ratchet

- You were trying to get him to be a little less grumpy

- He thought you were trying to change him

- He yelled at you and threw a wrench at you ( thankfully you were able to dodge the wrench )

Bumblebee

- He thought the only reason you were dating him is because you pitied him

- You were heartbroken when you read the note he gave you

- He felt bad after he saw how heartbroken you were

Arcee

- You had gotten kidnapped by Arachnid

- She was able to save you

- She thought you would be better off without her

Smokescreen

- He was being arrogant and careless

- You told him to be more humble and careful

- He got mad and broke up with you

Bulkhead

- Miko was practicing her flirting with him

- You thought that Miko was trying to make a move on him

- You broke up with him

Wheeljack

- He kept flirting with Ratchet

- You couldn't stand seeing him flirting with Ratchet

- You broke up with him