In my opinion, Spongebob is the best character because I think he's funny and the shows named after him. I don't really have a character I hate. The creepiest for me would be the leader squid that appeared in the episode "cephalopod squid" I think that's the name of the episode
Best: Nat Peterson. He has a job and family and hasn't done anything over the top that'd ruin the town or somebody's life. He's even thrown Plankton a bone by being his loyal customer even though he was in it for the money (which he could possibly need to help out his family). The execs at SnailPo really respect him too.
Worst: Patrick. He's demonstrated that his stupidity isn't actual stupidity so therefore anything he's done has been on purpose (Including eating Squidward's backstage pass tickets and making Spongebob think that he only had 1 copy of a rare card, only to destroy it beyond repair)
Creepiest: Spongebob. That one episode when Squidward said "What could you have possibly heard me doing" and Spongebob responded with "You breathing" is enough alone to take the creepy cake, yet I'm sure that's not the only incident.