Whats the big deal????

OK I understand that Dev could've refused to give his blood. Fine. But ultimately its just blood. It not like Dev and Maan hated each other and they were sworn enemies. They actually loved one another at one point. So WHAT if Dev gave blood. Everyone in the play is acting as if Dev gave Maan his kidney. The dialouges are even emoted to the extend as if Dev gave an organ. Whats up with that.