7. Your car was stolen when you left it running to warm up.

You don't want to make your car tempting to thieves, even if it's really, really cold outside. But if you do, your comprehensive coverage would typically cover the loss, but not always. "Negligence like this is normally covered," says Gusner,"but some policies exclude coverage if your keys were left in the car."

Besides giving car crooks a helping hand, be aware that leaving a car running unattended is illegal in some cities and towns. You could be hit with a fine.

Leaving cars running with the keys inside is a growing problem, according to the most current data from the National Insurance Crime Bureau (NICB). There were 57,096 such thefts in 2015, a 22 percent increase over the previous year.

Also, beware that thieves don't take holidays off. Though Halloween ranked highest for cars stolen on a holiday, New Year's day and eve are in the top five of the list compiled by the NICB. 

Holidays ranked by the number of thefts in 2016 were:

1. Halloween (2,578)
2. Labor Day (2,258)
3. New Year’s Day (2,242)
4. Memorial Day (2,139)
5. New Year’s Eve (2,110)
6. Independence Day (2,086)
7. Christmas Eve (2,054)
8. President’s Day (2,008)
9. Valentine’s Day (1,789)
10. Thanksgiving (1,777)
11. Christmas Day (1,664)