I'm 14 hours in, 65% done with the game, only 30 of the main story missions completed, and have not seen Prof Genki anywhere. I am really looking forward to the challenge of beating him, but I cannot find him.
I also hate this fucking challenge for 'Taunt X Number of Gang Members.' I'm only at 20 right now, but it seems like the number never climbs. I know I have to taunt gang members who are not pissed at me already and that it has to be a new person, but that number doesn't move.
I'll boot up the game, exit my safehouse, and start walking down the street. I see a Morningstar member, so I walk up in front of them, do my 'jerk-off motion' taunt, and he whips out his guns to shoot me. I then either kill him or call up my 'Reduce Gang Noteriety' homie and check the challenge number. No change.
Could it be because the 'Jerk-Off Motion' taunt is always interupted by them? That wouldn't make since though because that has been the only taunt I have used and I have gotten some points for it.
I spent a while last night at the airport farming challenges. The wheelie, stoppie, powerslide, and Big Air challenges got knocked out pretty quickly on a bike.
I did have something funny happen to me last night. I had a long day at work and ate a huge dinner when I got home, so I wasn't surprised when I got tired out of nowhere at 9 or so. I was playing the game and flying a helicoptor to one of my last diversions I needed to do. I get there, figure I will do a basejumping challenge while in the air, and fly to max helicoptor height. Then a bail out. I woke up to the sound of me splatting against the concrete and dying. Apparently I fell asleep after jumping out of the chopper and failed to open my parachute. I was pretty amazed.
I called it quits for the night after getting into a firefight and falling asleep and waking up to find myself spawned at the hospital. Musta gotten blasted...
EDIT:
My level 4 pistol with exploding bullets thoroughly disagrees with this statement.
My dual 'exploding round' pistols are awesome as shit. It makes me want to try the incendiary rounds or armor piercing rounds on a different gun. But then I think about how much I love the pistols and how awesome they are and I can't bring myself to spend money on the other upgrades.