On Beyond Zebra! (1955)
Context: In the places I go there are things that I see
That I never could spell if I stopped with the Z.
I'm telling you this 'cause you're one of my friends.
My alphabet starts where your alphabet ends!

“You want my opinion? We're all a little weird. And life is a little weird. And when we find someone whose weirdness is compatible with ours, we join up with them and fall into mutually satisfying weirdness — and call it love — true love.”

Dr. Seuss

Robert Fulghum in True Love (1998). Versions attributed to Dr. Seuss usually run "mutual weirdness".
Misattributed

“If you can see things out of whack, then you can see how things can be in whack.”

Dr. Seuss

As quoted in "Author Isn't Just a Cat in the Hat" by Miles Corwin in The Los Angeles Times (27 November 1983); also in Dr. Seuss: American Icon (2004) by Philip Nel, p. 38
Context: Nonsense wakes up the brain cells. And it helps develop a sense of humor, which is awfully important in this day and age. Humor has a tremendous place in this sordid world. It's more than just a matter of laughing. If you can see things out of whack, then you can see how things can be in whack.

“You're a fortunate guy.
And you ought to be shouting, "How lucky am I!"”

Dr. Seuss book Did I Ever Tell You How Lucky You Are?

Did I Ever Tell You How Lucky You Are? (1973)
Context: And suppose that you lived in that forest in France
Where the average young person just hasn't a chance
To escape from the perilous pants-eating plants!
But your pants are safe! You're a fortunate guy.
And you ought to be shouting, "How lucky am I!"

“It's opener, out there, in the wide, open air.”

Dr. Seuss

Source: Oh, The Places You'll Go!

“You have brains in your head.
You have feet in your shoes.
You can steer yourself
any direction you choose.”

Dr. Seuss

Oh, the Places You'll Go! (1990)
Source: Oh, The Places You'll Go!

“You'll be on your way up!
You'll be seeing great sights!
You'll join the high fliers
who soar to high heights.”

Dr. Seuss

“My alphabet starts with this letter called yuzz. It s the letter I use to spell yuzz a ma tuzz. You ll be sort of surprised what there is to be found once you go beyond Z and start poking around”

Dr. Seuss

“Be grateful you’re not in the forest in France
Where the average young person just hasn’t a chance
To escape from the perilous pants eating plants
But your pants are safe, you’re a fortunate guy
You ought to be shouting how lucky am I”

Dr. Seuss book Did I Ever Tell You How Lucky You Are?