It is not uncommon, yes?, for us to be approached by people who will begin their words with, "I need to tell you...". Experience confirms that this opening line is profound and significant because what we are about to hear will doubtless be gratuitous at best and irritating at worst. The opening words make it clear - the person before us has a personal agenda (sorry for the psycho-babble term) and it is for their satisfaction that we are about to be "blessed" with a generally thoughtless, selfish and often inane commentary.
So, I'm beginning to learn that best response to "I need to tell you..." is "Oh no you don't!" - end of that particular conversation. And if you find that a little unncessarily confrontational, why not try, "Are you really sure you need to tell me?".
Talking with couples before their wedding and marriage, I generally hear of people (sometimes well-meaning, sometimes not) who wish to proffer their advice, counsel and direction. My suggested response is to look the person in the eye, smile as sweetly as possible and say, "Thank you". Often the couple will respond and ask, "And then what do I say?". "Nothing, you say nothing more". This is not easy, requires a lot of practice and self-confidence but ultimately we get it and, perhaps more ultimately, eventually those offering the unsolicited counsel "get it" as well.
Try it! I know, you're saying "Thank you, Alan".