Paul Williams wrote this with Roger Nichols. It was an early effort for the duo, who went on to write hits for Three Dog Night and separately wrote popular TV themes: Williams for The Love Boat and Nichols for Hart To Hart. Says Williams: "As I examine my psyche, when I was an out-of-work actor, I had a movie called The Chase. I wasn't even writing songs yet. I was an actor before I was a songwriter. I did a movie called The Loved One with Jonathan Winters, then two years later I got another movie just like that, called The Chase. I worked three months on it, I think. My mom was a little widow lady living in Denver. And I brought her out to live with me. I said, 'Mom, you're never going to have to work again. This movie's going to really make me, it's going to be the big break I've been waiting for. My career as an actor is gonna just fly.' The movie came out and I'm not in it. I've got two lines, I think, the way it turned out. Big movie starring Marlon Brando, Robert Redford, Jane Fonda, Robert Duvall, huge film. So I worked on it, but I've got a little, really small part. So the career didn't take off, eventually the phone stopped ringing, eventually they took the phone out, eventually Mom got a job.
So I'd stay up all night, I'd started to plunk out writing songs. My mother would get up in the morning, and she's like, 'Don't worry, my son, God has a plan.' And she'd talk to herself, she'd mumble. And she'd walk away, 'oh jesus, I hope so...' I'd go, 'Mom, what's the matter?' She'd say, 'You wouldn't understand. I'm just feeling old. Just feeling old.' So she'd talk to herself. So I think that's probably where, 'Talking to myself and feeling old' came from, because she would jabber to herself, and whenever you'd ask her she'd say, 'I'm just feeling old today. I'm not sad, I'm just feeling old.'"
Sometimes song lyrics are written on the fly, and that was the case with a line in this song. Says Williams: "On 'Rainy Days And Mondays' Chuck Kay, who was head of publishing at A&M, said, 'That's a perfect song for The 5th Dimension, let's play it for them.' I said, 'Well, there are a couple of lines that aren't done yet.' He said, 'You'll finish it in the car.' So in the car going over there, I came up with a fill line, which was 'What I've got they used to call the blues.' I didn't have that line done yet, so I wrote it as just a quick fill line, because I wanted to mention the blues, but it was such a hackneyed expression, 'I've got the blues.' So I just wrote, 'What I've got they used to call the blues.' And it actually became my favorite line in the song. I think it's the best line in the song. I met Johnny Mercer once at A&M Records, and he sat down and I introduced myself, 'Paul Williams,' and he shook my hand. And he walked back into the studio where he was mixing, then he stuck his head back out into the hall and he went, 'Paul Williams, 'what I've got they used to call the blues,' that Paul Williams?' I said, 'Yes, sir.' It was funny. It was one of the great moments of my life, to meet Johnny Mercer, who I think was the lyricist's lyricist."