Difference between long running and long uploading

I'm just wondering. I tried running a script and it returned values fast. however, when I was trying to save it in Excel file, it took me two hours. I thought maybe because of the magnitude of data but when I checked, there were only 4++ records.
Tried creating a different script and it was long running. It took me 1&1/2 hours before it finally returned values. But I was able to save it in Excel file in a few secs.
What's the difference between long running and long uploading?
thanks