Shallow Depth of Field - Focus on Background

As mentioned during the critique session (Week 4), shallow depth of field photos work better if they have a certain kind of 'context' to it - meaning like it shouldn't be taken just for the sake of taking it/as much as the background matters, I think the blurred foreground helps to kind of 'frame' the subject in focus as well.

At least I hope I got that part right.

Two people admiring the white tigers. The white tigers are in focus here. I hope that at least it's more effective than the next photo.

A picture of an unused boat 'framed' by plants. The blurred foreground sort of gives it a kind of depth perception; the boats is perceived to be further away from the camera than if without the blurred foreground to provide the clue.
I think the photo has a kind of eerie feel, don't you think?