Why, Why, Why, take out insurance?

On the 1st of June I found out that I had a leak under my kitchen floorboards. There was over a foot of water and so I opened a claim with Saga who contacted their underwriters who are Legal and General who contacted a surveyor from BVS. I was told that as the water had not damaged the building there was no case and so it was closed. I had to repair the damaged pipes myself. HOLD ON THERE. Isn't that what I pay my insurance for? How was I to know that the pipes were about to leak? The legal jargon as usual does not explain in plain English what I was actually insured for. To cut a long story short I HAVE GOT ABSOLUTELY NO-WHERE, NO HELP FROM ANYBODY AND ABSOLUTELY NO INSURANCE MONEY. In what has been a really stressful 3 months I have sorted this out by myself and unfortunately paid for the repairs as well. I will tell you that I will be cancelling my insurance with Saga and will ensure that I will never again have anything to do with Legal and General.