One downside that immediately comes to mind is coming off as an a$$hole to the people closest to you, those who know you better than anyone else.
Without going into too much detail, I know someone who is the archetypal "Type A" personality. He is without a shadow of a doubt a legit narcissist, and definitely has sociopathic tendencies, if he isn't actually just a full-blown sociopath. He allegedly went through some sort of childhood abuse, so this only makes it more likely that his core personality was shaped due to it.
And when use the terms "narcissist" and "sociopath", I'm NOT using them in the way that a lot of women nowadays like to use them to talk about shytty dudes that they've dated.
Behind the scenes, this dude rules his private life with an iron fist, controlling every person within his inner circle with unchecked power, and has everyone seemingly afraid to speak out against him and the fukked up shyt that he's done to people throughout his life.
Yet in public, he portrays himself as a shining example of a Black male role model, presenting himself as an honorable good-natured man that others should look up to. He's held various leadership roles, is well-respected, and is very charismatic.
The only possible saving grace within all of his fukkkery is that the people who TRULY know him don't respect him. However, with his recently won lifetime achievement award and having acquired a network that consists of every prominent Black man in our city from activists, city officials, and even the mayor, the approval of those he deems "important" is probably all he really cares about anyway.
After doing some reflection on your question, I guess what attracts me to wanting to have a Type A personality -- especially during the time of my life when I made that post -- is the (perceived, at least) power that seems to come from it.
Power over others. Power over circumstances. Power in attracting women. Power over enemies. Power in controlling one's life.
I'm ultimately tired of feeling weak. Like my whole life up to this point was just due to a cosmic dice roll.