Paul continues in chapter 2 by reminding the church at Thessalonica of his behavior among them. For the first century reader the relationship is the most important thing and so it is essential that Paul remind them that their relationship was based on good behavior, positive experience and faithful dealing. We find this kind of reminder section in most of Paul's letters for example: he reminds one church that he never took money from them (choosing to pay his own way by making tents -- see 1 Corinthians 9); he reminds another how deep their love for each other has been (Philippians 4:1).
The subtext of this chapter asks an interesting question. Why is Paul's defense of himself so ardent? What we don't know, and can only speculate on, is the entire conversation that preceded the letter. One issue, as we shall see, has to do with the second coming of Jesus Christ. What other issues are in the background? Where there persons in the church challenging Paul's apostolic authority? Where there persons impeaching Paul's character? So in chapter 2 Paul defends his apostleship, his work habits, his "divine calling" as a preacher of the gospel, and other matters.
In Acts 17, we read that Paul's leaving Thessalonica was due to a riot. Paul seems to cause riots pretty much everywhere he goes. His hope is to return and continue the work . . . but he cannot do so until it is safe. Some of chapter 2 has to do with his hope to return and his inability, at the time of writing this letter, to do so.