Do not play football in the house with 2yr old Ds, then position football next to the Hoover and kick - you will kick the Hoover and break your little
Toe.
Don't try to catch a bread knife that you drop - you will catch it by the blade and cut 4 fingers.
Don't run the bath then close the kitchen door (downstairs bathroom) then go on Facebook - you will wonder what that noise is after a while and think the washer is on and that it's broken, before realizing the bath has been running for nearly 20 mins. Luckily we'd had a new bath put in the week before that did have a drain hole, which our previous bath didn't have - I didn't flood the bathroom thankfully.
Don't lock your ds1 aged 2.5 in the car forgetting that the old new car you'd got didn't have central locking. - it will result in the fire brigade eventually coming out due to it been a warm day.
Don't think you can get away with putting ds2 aged 2 in the bath, wetting his hair and tying it in a bobble and cutting above the bobble - it will look like a bob and he will look ridiculous the next morning on Christmas Day 
Don't give the boys chocolate when potty training 2.5 year old, take him into the bathroom to clean him up after an accident, leaving ds1 aged 1 crawling around. - he will find a stray 'piece if chocolate and eat it'. Then when you come back in wonder what Ds is eating and then wonder what that smell was. - as dh said to me when I walked in from work. Don't kiss ds2 on the mouth he's had a mouthful of shite
Don't push your sister head over the boiling kettle, she will end up with a scab on the bridge of her nose lol 
Don't tell your sister your going to pour bath water over her back (young kids me and sister) then fill the jug with boiling water from the tap.