Problem: How does the sentence end?

Robert likes to do yoga each morning but Jeffrey doesn't because
Answer: Robert has very flexible muscles.

Problem: How does the sentence end?

The child took to playing music on the guitar instantly but ignored the game because the
Answer: guitar was interesting.

Problem: How does the sentence end?

Natalie arrived at the hotel well after Elena arrived, because
Answer: Elena did not get stuck in rush hour traffic.

Problem: How does the sentence end?

So
Answer:
Brian trashed the house because Craig wants to live in a clean environment while Brian was messy.