I've been thinking about Locke vs. Jack a bit more, and there have been several occasions when Jack plows right over Locke. Locke is smart and has a lot of knowledge and skills, but he is not a leader.

In season 1, Locke says to Jack "Let me be the hunter, you go back and be the doctor" (approximately) and Jack ignores him.

When they are looking for Michael, Locke suggests turning back and Jack overrides him.

When they are tracking Ethan and the trail splits in two, Locke suggests they all follow the wrong path, while Jack insists on splitting in two and he is the one who ends up on the right trail with Kate's help.

Locke suggests drawing straws to give Kate a change to carry dynamite, but Jack ignores the result and carries it.

etc.

Several times, Locke put his own desire to get into the hatch, and thus find a role to appease 'the island', ahead of others. Jack is the one that gives the group hope at the caves when they are afraid the Others are coming. Locke sends Boone up to the plane and Kate down into the hatch, almost dropping her.

When the computer in the hatch was broken, Locke asked if he could help, and Desmond pointed out he was useless in that situation. Sayid had to come and fix it.

I don't have Locke figured out, these are just some observations. I think he wants to feel competent and important, and when that does not happen, he gets very angry. He also has no interest in getting off the island as his previous life was so pathetic.