If you're looking for manga similar to What a Wonderful World!, you might like these titles. All recommendations are made by Anime-Planet users like you!
20-something Meiko Otani is restless, living day to day with a job she hates and an unemployed boyfriend who'd rather be playing in a band. Like others her age, she struggles to find her place in the world and a purpose in life, so in an attempt to make a fresh start, she makes the decision to quit her job. Together with her friends, Meiko will embark on a journey of self discovery to find what will truly make her happy.
Well of course if you liked either Solanin or What A Wonderful World you would like the other, they have the same mangaka after all. Beyond the inherent similarities in art style and general mood, the first vignette of WAWW essentially was Solanin in miniature, and there were quite a few others that also gave me super-strong deja-vu. Not in a bad way, of course.
Two very moving, seinen titles that will invoke melancholic feelings from anyone who is past the age of 20 and experienced what it's like to grow up.
Same artists and author Inio Asano, the stories are great but the characters are going to grab you and keep you in. Wonderful, unique and completely original concepts on life.