What you see marked as junk is determined by your own junk filter settings. Other users have absolutely no bearing on the files that you see marked as junk.

The filter has to be trained over time...if it looks like too many files are being marked as junk, relax the filter a bit. Or, you can forget training data altogether & start from scratch It can take quite a while until the filter's working to your satisfaction & so it's a good idea to keep displaying 'junk'...often you have to go through & mark files as 'not junk'. It's part of training the filter.

This thread is long but it has some helpful info
Junk Filter

thanks for your comment, birdy

i did not know the signs were computed by my filter (i will have a look)

so, how do you explain this:
i put a garbage sign to the file "steven spielberg pranked call" (the one we all get, unfortunately), the sign stays for a while and then disappear?!?!?