Friendship Puzzle

Sometimes it is really hard for me to talk to somebody just like how I talk to my good friends
I can feel that there is thick and huge ice-berg in between us, preventing me to approach him/her
Why?
I have tried my best to be nice, be kind, and to be friendly, but still, I can't see the breaking of ice...
You may say this is my problem and I won't deny, because I just feel that something is not right..
Well I can describe the situation as:
"If friendship is like a jigsaw puzzle, he/she is not the right piece that can fit into it."
It is not his/her fault..that piece is just not belong to my puzzle, he/she deserve a better puzzle, anyway
Looks like it is time for me to let go, and search for a suitable piece for my puzzle.