An Unfinished Puzzle

I was given a puzzle when I was young and I finished putting the puzzle together with no missing pieces
I decided to show off my puzzle to my friends, and I started to notice some pieces were missing
I asked my friends if they took them
They said they would never. I believed them.
So I went to go buy new puzzles and find pieces that would fill these missing holes
The substitute pieces would fill the hole but the pieces never fully completed my puzzle
Things were out of place, and the substituted pieces never lasted
So it would take me a couple of weeks to find a new substitute to “complete” my puzzle
But I couldn’t buy a million puzzles to find a perfect piece to complete my puzzle
So now I’m left with an unfinished puzzle with strangers that holds on to the missing pieces to my puzzle