Yoshi has an odd personality. In videos after the debut of Mama Luigi, Yoshi lost almost all personality. However, earlier in "Season 0" of SuperMarioLogan, Yoshi plays a major role, revealing aspects of his personality.
Yoshi is Mario's deadbeat friend with a strange eating obsession. Yoshi eats almost anything, with no limits, whether it is food or Mario's collector's coin. Yoshi also is willing to commit crimes, such as when he doesn't pay and dashes at McDonalds in Yoshi Takes Mario to McDonald's. Despite this, when he does something wrong he feels regret and attempts to make up for it, such as when he takes Mario to McDonald's after eating his collector's coin.