I'm a little at some of them!
I think the worst advice I got was from MIL "Just give me a call if you need anything". Sure, I'll call the woman who abandoned her children on 4 different occasions before leaving for good on the 5th time when her kids were 8 and 12. The woman who used to smack her kids up side the head if they developed nervous ticks from worrying about her getting upset about their nervous ticks (confusing I know). The woman who, to help her son's ear ache, would blow cigarette smoke in his hear. The woman who, after seeing her son for the first time in 10 years, turned to his sister and said "well he's a bit weird isn't he?!". The woman who told her infertile (due to cervical cancer) daughter that she was a selfish baron old cow. Yep. I was definitely calling her for help...NOT!
Oh and my oldest SIL who told me not to worry if I had some bleeding at 7 weeks gestation because it was just implantation bleeding. For someone who had already gone through 2 pregnancy she obviously had no idea about how it all worked lol.