The final track on the CD, "Stealing Babies", features Elvin Jones, a prominent post-bop jazz drummer.

"[3] Mike Turner and Raine Maida say they wanted to make an album that didn't sound derivative, an accusation that had stung them in the past.

The band began writing, demoing and general jamming for Happiness... in late November soon after their appearance at the 1998 Summersault festival.

[7] Former drummer for John Coltrane, Elvin Jones makes a guest appearance on the final track of the album "Stealing Babies".

[9] They decided to hire Boston area multi-instrumentalist Jamie Edwards, who had formerly played with Blue Man Group and that Jeremy knew through a mutual friend, to augment their live shows.

[7] They strove to achieve a much simpler method of songwriting than on the previous albums which included tightening up songs and forming more cohesive tracks.

The mixing of the album was completed by late June 1999 when they played many of the songs for the first time for a large audience at Woodstock 1999.

[13] To promote the upcoming release of their album in September, Our Lady Peace performed a live in-studio concert and Q&A which was aired to 12 Canadian radio stations simultaneously utilizing satellite and ISDN technology.

In the band's hometown, Ben Rayner, the reviewer of The Toronto Star said, "...there's something curiously unmoving and dispassionate about it - it's canned angst ordered from some overstocked and increasingly disused alt-rock warehouse outside of Seattle, too studious and sterile to ever really hit you the way rock 'n' roll is supposed to.

"[22] David Gerard of the Boston Globe praised the guitar playing from the album, especially on the song "Blister" and also noted how the band had expanded its musical turf.

[23] Melissa Maino of The Buffalo News also reviewed the album positively, citing "Thief" as a stand-out track and saying that, "Our Lady Peace's music may be a little predictable, but if it's not broke, don't fix it.

"[24] In a 2.5 star review, the San Antonio Express-News praised the album for its high energy and subtle textures but criticized the vocals, saying "Raine Maida's overexposed falsetto is grating enough to send borderline psychotics over the edge.

"[17] The songs on Happiness... focus on a lighter melody, often following vocalist Raine Maida's extreme range of octaves sung in a falsetto-like manner.

Raine explained the album's overall concept in an early 2000 interview with Vue Weekly:[25] There was definitely a lot of talk around the studio about death and mortality and spirituality and trying to figure out what happens after this.

The track "Lying Awake" was said to be about Benny Hinn, and how Raine Maida viewed him as a con-artist, trying to scam people into religion.

The song features John Coltrane’s drummer, Elvin Jones, who played on the album A Love Supreme.

[26] Before their show at Woodstock in June, Our Lady Peace played a set of secret gigs in Muskoka and Toronto under the pseudonym Belly Flop Communist, at Jamie Edwards' suggestion.

Soon after the release of Happiness... in September 1999 the band set off on a tour across the United States opening with Oleander for Creed.

They returned to the United States in the Spring to participate in multiple music festivals such as Pointfest in St. Louis, Missouri, and SpringFest in Pensacola, Florida.

All tracks are written by Raine Maida, Arnold Lanni, Jeremy Taggart, Mike Turner, Duncan Coutts