"How I Met My Husband" uses first person narrative style to tell a story that becomes a classic example of paradoxical writing. These elements lend authenticity to the story, immediately draw the reader into involvement in the development of events, and support the build-up to the surprising and unexpected conclusion.
Your thesis could suggest that use of first person viewpoint is an effective method of promoting involvement of a reader in the action being presented in a story. In addition, use of this viewpoint allows the narrator to present the story in a manner that controls the revelation of facts to build to a surprising conclusion. In support of this thesis, you could then use passages from the story to illustrate your ideas.