Though Po's real passion was for Kung Fu, he was reluctant to disappoint his father by revealing it. Despite having a mild and friendly personality, Po also developed a severe self-loathing, believing himself a failure for being both obese (but in reality he is a healthy weight for his species) and a species not known for a warrior tradition. When he gets upset, he usually gorged on food to dull the pain.
His main interest lies in Kung Fu, of which he has developed an encyclopedic knowledge of the lore of warriors (he even knows the backstory of Master Croc, Master Storming Ox, and Master Thundering Rhino in Secrets of the Masters), famous combat moves, dates and historic artifacts (he even has action figures in the likenesses of the Furious Five which, as revealed in the credits of the second film, he made himself). Furthermore, his deep appreciation of the martial arts extends into its philosophical aspects, enabling to him to sometimes achieve insights of which even deeply respected masters like Shifu cannot conceive. Despite this preference, Po did not neglect his education in his foster father's trade and is an excellent cook as a result. However, as seen in the TV series, nobody can stand to watch him eat due to his very slobish behaviour (e.g, sucking up soup from a table, spitting it back into a cup to pick a small chunk of food from, then drinking said spat-out soup). He does seem perfectly capable of having manners though.
Po's personality can perhaps be compared to that of a fan of Kung Fu movies. He is generally friendly, lovable, passionate, a bit impulsive and good-natured, but sometimes comes off as chummy and informal, and his enthusiasm and excitable demeanor occasionally cause people to misunderstand him, most prominently in the first film. He is a big fan of the masters of Kung Fu and treats them more like heroes and celebrities rather than teachers and authority figures, which initially caused the Furious Five to feel like he thinks of them as entertainment. It wasn't until they put aside their expectations of the Dragon Warrior that they finally accept him as a good person and friend, rather than a disrespectful student who doesn't take things seriously