I find Flash Player a total pain.
Suddenly the installed v.19 wasn't good enough and wouldn't run on various sites.
I tried dozens of times to install the update, downloaded the installer file but when I ran it, it reported download error.
Luckily, Firefox provides a means to ignore the warning message and remember that action on that site in future, which rather suggests that many others have had this problem.
Now, Adobe Air is giving similar grief.
I hate Adobe !