I was too. Now that you realize it it's possible to never make that mistake again. Bishops lurking in the bushes at the end of long diagonals are never to be trusted again. Watch them, put them under lock and key, be suspicious of their motives. They're Moray Eels lurking in the dark.
A confession.
I recently discovered that I am blind in diagonals. I have lost several games because I did not notice the bishop threat. It finally hit me when a mentor lesson told me a certain move was correct, and it took me ten minutes to discover that I was blind to that move because I was ignoring the bishop diagonal.
I carefully check out knights, and rook files.