Simple PyQt5 counting GUI
Looks good to me!

super minor nits:

        thread = threading.Thread(target=self.something)
        thread.start()


only uses the thread variable once, so you might as well do:

        threading.Thread(target=self.something).start()


Also, the only thing you use from threading is Thread so you might as well change your import to:

from threading import Thread


and then it can be just:

Thread(target=self.something).start()


...but again, these are super minor things!  It looks good to me; I may have to look at pyQT again :)