Flippy and Flaky is the most popular shipping in the HTF fandom. It is unknown how it started but there is dozens and dozens of fanart and stories for this pairing.
Many fans think that Flippy has a crush on Flaky, and point to several episodes where he does not kill her as proof. A lot of fanart shows Flippy being cured from his PTSD because of her.
Some fans that do not like the pairing say that there are no true "hints" and claim that there is no proof of the couple. They often point out episodes where Flippy has Killed Flaky and the episode "Without a Hitch" which shows that Flaky is afraid of him.
There have been other cases when some of them complained that there are quite many rabid Flippy/Flaky fans who virtually attack those who do not ship the pairing. There is also criticism due to its perceived over-popularity, some of the critics sustaining that many fanworks involving it are cliche or fall into similar plotlines, or have disturbing themes such as rape. Some anti's are known for making Anti FxF fanart, and there is a anti FlippyxFlaky group on DA.