For me its because I do not code that mich, so when I coded like 6h a day for about 3 weeks I learned so much, that the stuff I wrote at the beginning of that 3 week time period looks kinda awful. There are some key elements that I would change if I would rewrite it, but I kinda dont want to, just for it to be a bit cleaner, since this would mean I would have to change a shit ton of stuff.