When you click on the box to enter your password, e.g. to change a username, the system always suggests a so-called "strong" password and you have to click to show you don't want to use it.
Why on earth is this? I get it that you may want to change the password occasionally, but the box is primarily there for people to put in their existing password, so 99% of the time people can't conceivably want to use the one the system has suggested.