It never happened to you ?
Sometimes... really sometimes... you click something and nothing happens.
Logitech mice for example have a long story of half broken mouse buttons after a couple years of usage but when it starts to fail and becomes irritating, how can you check for sure that your mouse is really defective ?
I just wrote a simple linux script to help you debug that while you are working normally on your computer. You can find it
Obligatory screenshot :