The passwords the system sends are randomly generated, and yeah, sometimes they're a little cryptic.
However, it's pretty easy to change to something easier. Log in using either your email address or your username along with the new password (they're case sensitive). Once you're logged in, select the Members menu option, then Update Profile. From there, you can change your password, change information in your profile, or upload/change a photo for your profile.
But... you can't do all three at once. The profile page is divided into three entry sections (and one help section). Each entry section has their own button to save. Complete only one section and save it before moving on to any of the others.