As for individual songs, "Follow You, Follow Me" (a love song about feeling safe when you're with the one you love) definitely qualifies.
In your arms, I feel so safe and so secure
And every day is such a perfect day to spend alone with you
The ending segment of "Supper's Ready", and the lead-in to it; after a foreboding section about the apocalypse, the music becomes much more subdued as Peter Gabriel sings a reprise of "Lover's Leap", followed by the instruments coming back in soon afterwards. The last part of the song sounds so triumphant, like a celebration, that it's hard not to feel at least somewhat happy listening to it.
Later on, in the closing moments of "Los Endos", the last track on A Trick of the Tail (the group's first album without Peter), Phil Collins sings "There's an angel standing in the sun, free to get back home" in a reference to the above-mentioned part of "Supper's Ready" as a tribute to Peter.
Also from A Trick of the Tail, the ending of the Title Track. The protagonist, one of a civilization of satyr-like "beasts" who live in a utopian City of Gold, gets bored and leaves to explore the human realm. Once there, he's captured and imprisoned in a freak show. Fortunately, he escapes and returns with a new appreciation for his world, and his people are happy to take him back. The song's last line:
Hello friend, welcome home
On January 31, 2016 (the day after Phil Collins' 65th birthday), the band's official Facebook page (as well as the pages for Phil, Tony Banks, and Mike + the Mechanics) posted a photo with a caption along the lines of "Old friends catching up in London last night..." The photo in question featured the trio standing together and smiling. Considering how many long-running bands have had their core members end up hating each other's guts (and that's if those members are still alive), the fact that (at least) Tony, Phil, and Mike are still close friends is very special indeed.