I always think glad it had enough on it to finish my project. What I don't like is when I go to get a replacement I can't get the same colour.
Birch threads here in Australia used to have a lovely Gold shiny but not metallic thread. Well it finally ran out and shop no longer stocked threads so found someone online selling it. Ordered the correct colour number but it was so different. That made me sad.
I always talk to my bobbin when it's almost empty and I'm close to the end of my project. Such a good feeling when I don't run out before the end of my project.
I love that feeling too. I save all the spools, some I use over with bits of lace, some I clean and make toys with. the old ones I find with good labels on, I put away.
I want to hold it up and say "look what I did!" I guess the inner child (and maybe my crazy) is showing a little on me.