In every episode Spongebob is Patrick's best friend. The majority of the episodes Sponge bob is actually more of a family member. Often, times they have sleepovers and in one perticular episode they raise a baby clam together. Like any other normal best friend they are always helping each other out, well, mostly Spongebob helping Patrick out. Spongebob allows Patrick to help out at the Crusty Crab in multiple episodes, and Spongebob is usually planning his days around Patrick, so they can hang out. Also, most of Parick's friends are through Spongebob.
Spongebob inroduced Sandy to Patrick, and now they are really close friends. Sandy however, the genious of the bunch, finds Patrick rather annoying. She is often referring him to an idiot and not letting him join in on certian activities, because she feels he will mess it up. Patrick is quite oblivious to this and still treats her as abest friend. In this situation "ignorance is bliss." Patricks inability to understand the true meaning behind some hurtful words, allows him to be an honorable friend.
The audience looks at Squidward as more of an enemy, but Patrick is always referring to him as a friend. Again, Patricks stupidity is landing in his favor. Patrick doesn't care what people say about him so he lives more of a relaxing life. Even with the amount of rude comments Squidward sets on Patrick, Patrick is always returning with a happy attitiude.
Patrick doesn't have the best connection with everyone, as he does with Spongebob, because the other characters feel annoyed by him. However, he is a floater and when it comes down to it he is friendly with everyone.