Are You Something or Nothing?

Galatians 6:2-3 NASB
2 Bear one another's burdens, and thus fulfill the law of Christ.
3 For if anyone thinks he is something when he is nothing, he deceives himself.

According to verse 3, how might a believer deceive himself?
If he is deceiving himself, what might he not be capable of doing?

Let's check the cross-references for this verse.
The first one is Acts 5:36.
In this example, who claimed to be somebody?
What happened to him?
According to Galatians 6:3 was this person deceiving himself?

The second one is 1 Corinthians 3:18.
What should the man who thinks he is wise in this age do?
Why should he do that?
How was the man who thought he was wise in this age deceiving himself?

The third one is 2 Corinthians 12:11.
What does Paul say he has become?
What does he think his position was in respect to the most eminent apostles?
What does he say that he is?

Reread Galatians 5:13-6:3.
Why does Paul tell them that if they think they are something when they are nothing, they are deceiving themselves?
How does this verse relate to the ones that came before?
If we are to be burden bearers, what do we need to lay aside?
If we are to be burden bearers, how should we be walking?