i just finished watching the show and even tho it goes down as the best show I ever watched i still don't understand why spike had to go on a suicide mission especially after the death of julia since he has nothing to save and even tho he couldn't escape from his past i really wished if he just moved on just like the rest of the crew did and go back to those adventures as a bounty hunter but at the end "What happens,happens"
I think his chains to his past dragging him down long after it can be fixed makes a lot of sense and delivers the message of the show in a really powerful way.