Many also get drastically overfunded, and the creators totally go off the rails with grandiose plans, instead of following their original, achievable goals.
ie. if we're funded between a to b we'll deliver a prototype unit, but over b we won't deliver any more until we hit c. Hitting the initial funding goal opens up a stretch goal that is independent (backers are backing the stretch goal, not the initial campaign and won't get rewarded unless it's also hit)
I've stopped funding Kickstarters once they're significantly over their goal; I don't think it helps, and I can just buy their product later anyway.
The latest thing on my list is the Marbel skateboard. Looks great on paper, all the tech exists, other [small] companies are doing it, but they've had tons of delays and I don't trust that their first products sent out won't have some kinks. I'm not really willing to pay the early adopter fee for a vehicle which could cause me great bodily harm if it malfunctions (e.g. Bluetooth has interference problems or randomly disconnects, which would definitely not be unprecedented in the world of e-skateboards).