Firstly, you've got the idealist souls. These are the people who rush enthusiastically to the end of their first draft and believe that their job is done. Of course it's perfect: they wrote it. Why wouldn't it be perfect? Distance is alien to them and perhaps they start submitting the manuscript straight away to anyone they can think of. If they're an absolute genius of Dickens or Woolf proportions then it gets them where they want to be. For the rest of us, we must start scribbling away at that second draft, often a major overhaul.
Once you close in on the end of that draft you become an optimistic soul. You've probably lost your initial enthusiasm for your project but you recognise what you have now is better. However, since you've spent all this time fiddling about with the plot and characterisation, your prose reads like cardboard. Your images are all muddled up and at some point you described your protagonist in very biblical language which may or may not indicate you believe him to be the saviour of mankind. It needs fixing.
When you enter the third draft you're more of a hopeful soul. You're praying that the novel will be done at some point but you think you might have numerous medical conditions before it is. But, still, when you reach the end of it, it looks better than it did at the beginning. Of course it does. It's not like you'd waste time, is it?
Then you enter the stage of the obsessive souls. These are the people who are happy with their plot, happy with their characterisation but can't leave the manuscript alone. The number of drafts spreads into the teens, with no real tangible differences between them. Perhaps a word has been altered or an image bettered. This novel isn't going anywhere, except through the printer so you can edit a few words again.
I realise that I'm in danger of falling into the latter category. I'm insistent that there needs to be a fifth draft of this manuscript and I swear I'll consider letting it go after that. However, I do have a legitimate reason for another edit: I've substantially changed plot points in my fourth draft and, as a consequence, I need to check all that makes sense and do some polishing.
Will I be able to let it go afterwards? I may need some of you kind readers to pry it from my hands...