Links from external sites - good or bad?

As a webmaster, you can see who links to your site by looking at the access log of the web server.

Links to your pages are something good - it brings people to your site. But what if there's a bad comment about what you have on your site?

Some times it's not easy to find out what the referring URL is talking about - see these examples:

Italian

Russian, more Russian

Polish

German (ok, that's easy for me)

Chinese more Chinese

Sometimes wrong information links to your site and leaves you wondering if you should try to correct it, or unfriendly companies suddenly start to send visitors over

I am just welcoming all visitors to my sites, no matter where they come from.

As not everybody reads english well, I have started to provide URLs to have my sites translated to their language - maybe that helps them to understand what I wrote just like it helps me to understand what others write (about my sites).