From your question, can guess that you're confused liao.
Metering is about 'exposure' (ie bright/dark).
Wrong metering does not make your subject 'blur', but only either too dark or too bright.
When you press shutter in AUTO mode, 'basically' 2 things happen in your cam.
1. it measures the light entering and determine the exposure for you.
2. it focuses on your subject.
So only focused on wrong subject (or handsake) will cause your intended subject to be 'blur'.
When the cam does 'metering', few possible options are available:
- average (take the overall average reading of light from the whole frame)
- spot (only sample on the amount of light where your 'bull-eye' is aimed.
- centre weighted (combination of the above 2)
- matrix (or similar term. Different from manufacturer to manufacturer, cam to cam)
So for SPOT metering which you're asking, it'll ignore other areas of the framed pic, whether they're over (too bright) or under (too dark) exposured.
Many many more to it, above is just a very simple explanation to jump-start.