Most Difficult Sentence to say in any language!!!

I was generally browsing some websites and stumbled upon this site which had put up some words as the "Most Difficult Words to Pronounce in English". The words were outright scary.. The words had 30 letters+ each.. How could anyone think up a word with so many letters???? Phew!!!!
This also got my thought to an interesting question.. Which is the most difficult sentence to say? When I say "to say", I mean saying it to people who care for us and vice versa.. The only one i could think off which we really struggle to say most often is a very simple one. In English, the sentence has just 3 simple words and 8 letters in all.. But coming to think of it, probably the most difficult for any of us to utter to the ones who love and care for us.. Interestingly, the same words blurt out our mouth almost instantaneously and without a second thought to a lots of strangers all around us..
Why is it so difficult for most of us to say "I AM SORRY" to people who really love us ??? Even when we realise we have goofed up big time, we don't want to relent and say it.. However, We bump into someone on the streets and we automatically blurt this out..
Wonder what stops us from saying this to the people we care about and who care about us?? Is it that we take these people for granted and think we can get away with anything with them?? Is it our Ego?? or is it the fear that we won't be forgiven for what we did wrong??
I have known for 5 years that I need to apologise to someone, for whom I was extremely important, because of having done some things wrong.. But, till date I have been unable to say it and still can't make up my mind to utter these 3 simple words. It didn't take me long to realise I had not done it right and what my mistake was. Having known this, I just couldn't get myself to apologise to the person whom I had wronged.
Incidentally, when someone important to me was cross with me and I had no clue what I had done wrong, It didn't take me long to go down and ask for forgiveness for something which I might or might not have done wrong.
Don't know if I ever will find the answer to this question -Why? But, "I am sorry" would definitly be one of the most difficult sentence to utter in any language..
If I ever find an answer to this, I shall post that as well.. Until then I guess it will stay unanswered and I shall hesitate to say it!!!

Kiran!!!