My children

Why oh why do they see the need to wreck everything?! Mainly my 4 year old. She has to mess with everything in sight! I brought me some books and she ripped them apart page by page! I brought her an activity bag with paint in and she waits till I'm in the shower or pegging washing out to 'redecorate' her bedroom walls.... If there's a pack of baby wipes around (as I also have a 1 year old and due my third baby in 2 weeks) she will take every single wipe out the pack and rub them over the floor. She throws dinner around breaks toys and is overall disctruptive.

Anyone have any clue why? I'm posting anonymous as I know there will be comments along the lines of I'm just a bad parent. But truth is no discipline seems to work with her! Putting her in time out. Taking toys away. No treats. Praising her when she's good. Getting down on her level.... Absolutely nothing works. Any advice?