Healy was inspired to write the song to confront his fear of sincerity, using postmodernism in the lyrics to denounce sardonicism and irony, choosing to portray vulnerability and honesty instead.

The song contains a hip hop production that incorporates layers of brass, trumpets, horns, saxophones, lounge piano riffs and a steady drum beat.

"Sincerity Is Scary" received generally positive reviews from contemporary music critics, who mostly praised the production, lyrics and thematic depth.

[1] Speaking to Zane Lowe of Apple Music's Beats 1 Radio, Healy revealed that the song is meant to denounce his postmodern fear of being authentic.

[3] After having previously worked with them on I Like It When You Sleep, for You Are So Beautiful yet So Unaware of It, Healy lauded the choir as "amazing" and wanted them on A Brief Inquiry into Online Relationships, saying: "It wouldn't really be a 1975 record without them on it.

"[4] The London Community Gospel Choir recorded their vocals at Abbey Road's Studio Three, which were engineered by Chris Bolster with assistance from Daniel Hayden.

"[6] Hargrove died two months after the song's release, an event that Healy called "heartbreaking", noting the instrumentalist was the first non-band contributor to feature on one of the 1975's albums.

The singer took to Twitter and encouraged the band's fanbase to listen to "If I Believe You" (2016) and "Sincerity Is Scary" in remembrance of Hargrove, who Healy assured "made those songs so special for us".

[3] Thematically, "Sincerity Is Scary" deals with modern communication problems, allowing oneself to be vulnerable, Healy's limitations as a songwriter and his struggle with heroin.

[20][23] Later, Healy addresses social media surveillance, self-knowledge and a communication breakdown ("And why would you believe you could control how you're perceived / When at your best, you're intermediately versed in your own feelings?")

[22] Jarrod Johnson II of Paste felt the song addresses the mental hurdles of reduced transparency and honesty in modern-day relationships, both socially and romantically.

[25] Maura Johnston of Rolling Stone interpreted religious undertones, calling it "a shuffling rumination on the gaps between people that underscores Healy's hoped-for leap into faith".

[17] Marissa Lorusso of NPR noted that the chorus of voices in the refrain are evocative of the "more touching" numbers on the 1975's second studio album,[21] while Joe Goggins of Drowned in Sound said the inclusion of Hargrove is more specifically reminiscent of the band's "If I Believe You".

[15] Echoing Goggins' statements, Caitlin Ison of Atwood Magazine said both songs share sonic similarities owing to the use of gospel choirs in their choruses.

[26] Robin Murray of Clash praised the 1975's incorporation of jazz in "Sincerity Is Scary" and noted influences of A Tribe Called Quest and Gang Starr that are "filtered through a 1975 lens".

[15] Danny Chau of The Ringer said the song was one of the most surprising stylistic choices on the album, praising Hargrove's contribution and comparing the composition to the Soulquarians and Musiq Soulchild.

[29] Shannon Cotton of Gigwise called the song smooth and sultry, saying it "makes you feel like you should be sat on the rooftop of a New York apartment, with a cigarette in one hand and an expensive glass of red wine in the other, gazing at the skyline".

[20] Lorusso declared it the most exciting single from A Brief Inquiry into Online Relationship, praising Healy for providing an earnestness that "positions him as a try-hard worth rooting for".

[34] In a negative review, Roisin O'Connor of The Independent compared "Sincerity Is Scary" to a throwaway Ed Sheeran song, calling it a "sickly ballad that frontman Matty Healy claimed was about dismantling his ironic shield, but if anything this sounds as false and insincere as anything else they've released before".

Speaking on his experience working with Healy, Fu said: "When it comes to music videos, it never ceases to amaze me when sketches on a whim materialise in person a few days later on set.

[43][53] Upon reaching the bottom of the stairs, Healy begins to sing the song on the bright, busy and colourful street, greeting strangers and sharing kindness as he performs retro choreography.

[43][45] Continuing his walk down the street, Healy encounters a man wearing a paper bag over his head that reads "A Brief Inquiry into Online Relationships".

[43][45][46] The singer performs a dance sequence evocative of Jackson and gives his hat to a child before dashing to a lamppost, swinging around it in reference to Gene Kelly.

[49] The Dork editorial staff compared the visual to a mix between the white rabbit from Alice in Wonderland (1951) and Fred Astaire, praising Healy's dancing, "winningly likeable smile and [the] spring in his step".

[53] Patrick Campbell of Don't Bore Us called the visual "incredibly fun" and praised the less-serious tone in comparison to the previous videos released from A Brief Inquiry into Online Relationships.

[57] Maggie Serota of Spin wrote: "['Sincerity Is Scary'] has everything, up to and including choreography, sick soccer moves, a child in corpse paint, and what appears to be one long tracking shot.

[62] Daniel Welsh of HuffPost ranked the visual at number 18 on his year-end music videos list, writing it is: "At once both completely pretentious and utterly silly, which is actually a perfect description of the band themselves.

He posted a photo showing a text message conversation between himself and Healy, saying he is a "massive fan" who heavily respects the 1975 and made "an honest mistake [...] [I] want to do whatever [I] can to make this right".

Healy humorously replied, "[your] mums a hoe", telling Lauv he did not mind the similarities and encouraged him to post a screenshot of the messages in response to the criticism.

The band's performance mirrored the song's music video, featuring Healy wearing a knit hat, a backpack, a pair of headphones and a tuxedo.