You probably focus on something without too much contrast, you zoom in too much or you try to focus too nearly.
It is, however, very common to check after each shot if it's in focus
You want to have the best shot, dont you? And if you can check -at that time- if it's going to be a good shot and you can change the focus to be sure it's going to be a good shot, then what lets you not check it?
The best way to focus on a compact camera is to use the center point only. Then you focus on what's in the middle of the viewfinder, and 99% of the time it's spot on.