Here's a strange one.
Looking at the analytics for a site, I spotted a search phrase that had brought in a visitor:
"[arabic word] [widgetmake] [widgetmodel] [year]"
I did the search on google.co.uk and sure enough the site ranked 4th for this phrase. All the other sites in the SERPs are arabic sites, just the site I'm working with is a UK-based, English language site.
I translated the Arabic word, and it means 'prices'.
If I change it for the English word prices, and do the search, the site no longer ranks in the top 20 results. The same when I simply removed the word from the search query. What factors could make it rank so highly with the arabic word, but not at all without it? Like I said, the site is wholly in English, and is aimed at the UK market. I had some other people test the search, and they are seeing the same thing as me - so it's nothing to do with my search history, G+, etc.