There are more than 7,000 Firefox extensions in Mozilla's official catalog, and a good portion of them can drastically improve how you browse the Web. Then there are the stinkers. These add-ons that actually make the browser slower, or harder to use. We've compiled a list of 20 that you should steer clear from, if only for their lack of basic utility.
It's worth noting I went through more than 7,000 extensions to come up with this list and it was incredibly tough to even come up with 20. It can also be argued that some of the ones on this list are, in fact, useful to a select few.