This episode confirms that Vicky has hardly any friends, and the ones she does have are coerced into following her. Not only that, but the babysitters in B.R.A.T. look hardly older than Timmy, let alone teenagers like Vicky, meaning she likely does not have any friends in her age group.
Grim Reaper - The hooded figures of Vicky's friend are based on the Grim Reaper.
The Powerpuff Girls - The animation of hearts when Vicky hugs Timmy, is similar to the ending gag of every episode of the series with the narrator saying: "And so once again, the day is saved thanks to... The Powerpuff Girls."
This episode shows that Vicky has a heart, but in Tiny Timmy, it was revealed there is just a black hole in that space (Timmy even noted there that the black hole is her heart).
How did Cosmo get his ears pierced with Timmy and Vicky? He would have been spotted, and Timmy would lose his fairies forever. However this may not count since the people who gave Cosmo the piercings did not find out that he was one of Timmy's fairy godparents since godparents will only go away forever if people find out whose godchild the godparents belong to.
Lots of people could have noticed Vicky torturing Timmy in the beginning, meaning Vicky could of have gotten fired.
Also at the beginning, when the tar trucks pass, you notice that no one is driving the trucks. Also the front-loader doesn't have a driver.
When Timmy says "Hey Fishy Fishy". If you look close Wanda's tail is missing.
Vicky is still a huge fan of Chip Skylark, despite the song Icky Vicky, which is about Chip Skylark's hate of her and the fact that she no longer liked him after finding out he is not rich.
Vicky saying "forever and ever" many times to Timmy
Vicky making weird acronyms for Timmy and words coming out of nowhere.