Meanings of own ineptness in английском

Why feel sorry that a multi-millionaire's dream has died given its largely due to his own ineptness?

Mortified by the consciousness of his own ineptness-orineptitude-thefellow was simply trying to hamper and obstruct.

As much as the Flames were victimized by Pettersson and Markstrom, they were victimized by their own ineptness, especially while on the power play.

"Strike refused to leave it with me." Alone in the dark, I felt myself blush with humiliation at my own ineptness.