Why did my night pictures turned out so foggy, light or too bright?

It looks like your example was severely underexposed. When the negative was scanned or a print was made from the negative there was an attempt to brighten the image to give you something more than a totally black frame.

For exposures longer than one second or so, don't forget to account for the Schwarzschild effect, sometimes referred to as reciprocity failure. The sensitivity of films at longer exposure times is not linear. This can very significantly impact exposure times, and it varies by the specific film in question. The manufacturer's data sheet of your film should provide information regarding how much compensation is needed for longer exposures.