Examining [I+must+admit+I], we found that the construction is typically preceded by a positive or neutral comment on the state of affairs in the prior turn but is usually followed by a strong opinion or disagreement incorporating the speaker"s feelings (e.g., disappointed, fed up), conviction (e.g., sure, convinced), disposition (e.g., dowdy, older) or desire (e.g., looking forward to, keen) such as "I must admit I don't think we get offer really frequently", or "I must admit I'm getting a bit fed up with it now".
[I+must+admit+I] performs an orienting function by directing the communicative partner"s attention to an opposite view point or a negative remark that may sound disagreeable or upsetting.