Is my wife right to be angry?

I am currently in the doghouse with my wife. A few days ago, I decided to play humourous wheeze. She owns a portrait of herself as a child, which was painted by her uncle, whom she loved dearly and has recently died in tragic cirstances. Anyway, I decided to pretend that I was burning it in the garden, by using the same shaped frame and setting it alight in a brazier. Unfortunately, I picked the wrong painting and ended up burning the real painting to a pile of cinders. When I told her, she cried a great deal and used a selection of curse words. I told her not to be so angry, as in all honesty, the painting wasn't very good anyway. Who is right here?