Leo's pet fish is named 'Opie'. The name was picked because original footage from The Andy Griffith Show (1960) was purchased from CBS and the rights cleared. However, days before filming the gracious Mr. Griffith unexpectedly refused "likeness permission" - so it was Andy "86'ed" but Opie stayed.
The director conceived and wrote the screenplay based on a real-life stalker. In this case it was a woman and she dedicated her life buying expensive gifts for her "one true love" and showing up conveniently at every job and social event he attended. After several restraining orders she ultimately gave up by committing suicide.