cheekychops, I find your attitude rather sad, particularly as you have no idea what is on the negatives.
They may be a facinating slice of life in the 1950s or 1960s.
As an example, have you ever heard of Mitchell and Kenyon?
These were two men who went round the North West of England in the early days of film making (1900s). They filmed ordinairy every day things to show in small cinemas or local vilage halls.
People paid money to see themselves on film for the first time.
When these men died the films sat in a basement for 70 years and nobody knew they were there. When they came to renovate the building someone found them and they have now been restored (at a cost of millions of pounds).
They now give a facinating look at life during that period, what people wore, how they lived and so on. It even includes they earliest clip of a football match in England (Manchester United I think)
You can see some clips from the films here:
http://www.bfi.org.uk/features/mk/
Supposing the person who found these films had done as you suggested and thrown them on the fire. We would have lost a slice of our history.
Maybe when you get a bit older you will understand.