Just found out this tiny bug – it looks like the mail search in GMail is conflicting with its own keywords 
Go to your GMail account and click on the Spam link on the left. When the contents of the Spam folder appear, look at the content of the search box above: it says in:spam. Apparently, GMail uses in:spam as a keyword to indicate “search for this in the folder named spam“. You can try this out by tiping in:sent mail ticket - all your sent mail containing ticket pops up. Cool.
Now the bug: type in:spam in the search box and click on Search Mail; you’ll get the content of the Spam folder (we know this). Now do this again – click the Search Mail button again. You’ll get the content of the Spam folder again (duh!), BUT WATCH: notice the ad served to you by Google on the center window’s title…it’s something about spam, most likely a recipe (e.g. “Spam Confetti Pasta – Preparation time 30 minutes“). Apparently Google sees that the search box – or the spam folder – contains spam and serves ads for spam, forgetting that it’s a keyword. It’s kinda like if you searched Google for site:phone.com ticket and Google served ads for phones
