Meanings of painfully plain in English

My ostracism was painfully plain to me, and, as was my nature, I brooded upon it in silence.

Withal her need was painfully plain.

Panoramic views are painfully plain.

We all know of the most gentle, lovely, unselfish spirits, beautiful to Heaven's eye, that are enshrined in painfully plain caskets.

Accompanied by these refreshing cogitations, Guy reached his comfortable office, but oh "how painfully plain an index to his troubled soul was his worried face."

"It's all painfully plain to me," he said with a spice of bitterness.