Yotsuba&! is great! I wish it got more recognition as a hilarious manga rather than just a stepping stone for Japanese learners.

My favorite though is Kaguya-sama: Love is War. The characters are all insane in the most perfect ways. Skip and Loafer is a close runner-up though; I love its characters for all being so grounded they feel more like people than manga characters. It’s a very different feel than I get from other manga.