Just off the top of my head:
#1 - The fact there aren't 30 hours in a day
#2 - ICANN madness and some of the most dumbfounding decisions ever!
#3 - People who use my daily lists but don't use the affiliate links or even bother to click thanks/like.
#4 - Auction bots that click faster than me.
#5 - Auctions wins that are clawed back
#6 - Lack of a
good auction platform.
#7 - People who refuse to listen to logic at NamePros and continue to post misinformation harmful to new domainers.
#8 - The fact my computer (actually a good one) can't handle my complex excel masterpieces!
#8a - Microsoft!
#9 - Platform bugs that are eternal.
#10 - People who place any importance on automated valuations on single domains (and I'm actually a happy client of Estibot .. lol)
.. and the list goes on ... lol ..
FYI ..
@Michael Cyger didn't actually sell DomainSherpa .. he actually ended it to move on to other challenges (including DNAcademy) .. and then MediaOptions came in and bought it to keep it alive a few months after Mike closed it. Mike's a domain baller now .. small portfolio of top notch high-5 and 6 figure domains (with the exception of his unicorn .. on which he is probably riding off into the sunset .. lol)!