The color seems to match up perfectly to fill the space. The notches and the angels appear to be exactly what is needed to slide easily in place, but it doesn't. You turn it around, upside down, and backwards, but regardless of the position you put it in, this puzzle piece simply does not fit.
These sort of experiences will consume you throughout life. You mull over one piece, convinced it has to fit, and try to force it into place. You keep pushing it down and even go back to it many more times, something just doesn't feel right about it in the context of the rest of the puzzle. Then finally, after you get many more pieces of the puzzle put together, you see it, the piece that you didn't expect to find, the piece that allows you to take the forced piece out and replace it with the piece that fits perfectly. The piece you removed is needed to fill another spot in the puzzle, one that is necessary, but not the one that will give you the greatest gratification as you admire the picture when complete.