As others have noted, I see nothing nefarious in the OP's post. He's just trying to run CCleaner too quickly after he closes his last Firefox window. Exactly how long it takes his OS to completely shut down Firefox of course depends on several things, most of them not under Firefox's (let alone CCleaner's) control...
I stopped caring about cookies years ago. Do you remove the tracking cookies from your smart phone? of course not. So why do it on the PC? Don't you get tired of having to re-longin to everything (like AT) every time you run a sweep?
You are going to see ads every where you go on the internet. The tracking cookies are just making sure you see ads that might be more tempting. That's it.
But when I'm not using an adblocker, I'm ignoring the ads anyway, so whether they're "targeted" or not is irrelevant... And no, I really can't say I get terribly "tired" of taking all of 5 seconds to log into the sites I use that require logging-in (not that many, anyway).
I don't own a smartphone and haven't yet replaced the tablet I lost back in April (or more precisely, which was stolen from the city bus I stupidly but inadvertently left it on instead of being turned in to the driver, unless of course the driver himself stole it...), but you can bet your bippies (whatever a bippy is) I deleted cookies from my tablet, though not quite as frequently as I do from my PC (which is very, very often throughout the day), though I also didn't use the tablet for web surfing much to begin with, and then almost exclusively to visit the same few sites. And yes, when I eventually get around to getting a smartphone, I'll do the same on that.
And no, btw, I don't own (let alone wear) a tinfoil hat and I'm not afraid of the NSA (or my ISP and the multitude of law enforcement agencies that can get at my data from them, let alone the miscellaneous "hackers" mainstream media love to terrify the general populace with.) I just don't like the idea of my web-surfing habits being monetized ubiquitously and as a matter of course (at least without even token compensation, like retailer "loyalty program" discounts) and so prefer to keep the various tracking/marketing companies' database entries for me as small as possible...