1) Grass is generally green

2) First salesman is wearing a made up brand of shoes

3) House number should be 23 not 6.

4) No glass in the windows

5) Man in window is not wearing his glasses so should not be able to see the Sales men coming.

6) Colour of curtains doesn't match the colour of the house.

7) 2nd salesman has his pants on inside out

8) Cat is really a dog in disguise

9) 2nd salesman is wearing a pot instead of a hat

10) House in background is being burgled