best intentions 

Some of the worst things have happened with the best intentions

To do something you think is morally right that may end up wrong

I had the best intentions when I kept the secret that her sister had a pregnancy scare with her best friend

best intentions by ialem July 29, 2018

best invention ever 

The Bong.
The physics of this device are purely brilliant, allowing stoner's to smoke in style instead of burning our mouths and lips smoking joints.

The bong is fully the best invention ever.

best invention ever by Diego September 29, 2003