SPOILERS) pretty good movie "Limitless" - gaping, massive plot holes?

I enjoyed the movie, good popcorn flick; but first of all, the "we only use 10% of our brains" one of the biggest myths in pop culture. Neurologists find it laughable that people buy it (its also used by cognitive therapists to further support of their study). Secondly, this pill is extremely sought after, worth killing for, extremely rare, incredible expensive, officially doesn't exist, possibly the greatest discovery of mankind's history... and some guy's ex-wife's brother who he didn't really get along with and hasn't seen in a decade (who's totally aware of the pill's value and implications) just decides to give one to this guy? Out of the blue? I kept expecting a twist in which the bro-in-law had been setting him up or using him as a guinea pig or something, never came. Dude just hands over this priceless, dangerous miracle pill to a former half-relative so he can get his book going? Another gaping hole is that Bradley cooper, a super-genius with a flawless memory of every experience he's ever had in his life, who just made 2 million in a week, forgets to pay back a russian mobster he borrowed 100k from a couple of weeks earlier? A mobster who tells him that if he rips him off, he'll peel the skin from his waist up and asphixiate him with it? And near the end, this pissed off mobster manages to use a saw to break into an unpenetrable fortress of a penthouse that bradlehy cooper paid over six million dollars for? Without the cops showing up or anything? (i know, they kill the neighbor who comes out or whaterver, but still, the security in a place like that would be state of the art. Hey Brad, pulling the f*****ing alarm! And when his gf is trapped behind the rock at the park from that creepy stalker, she takes the smart pill and her brilliant plan is... to run a few hundred meters to a skating rink and flip a little girl around, cutting the creepy guy's face? This dude is chasing her through a very crowded area, full of people, in broad f*****ing daylight, with a bloody knife in his hand, and no one says boo? Anyway, great example of an entertaining movie in which you really, really have to suspend disbelief.