Where they do excel is at shmoozing their new boss into accepting them, even to the point of getting an Ax-Crazy villain to not just let them live, but convincing them they're more useful alive and working for them. Interestingly, they are usually at least competent at their job as personal assistant, though rarely to Hypercompetent Sidekick levels. Just like they lack ambition, they are also devoid of all malice both because they, at times, qualify as a Minion with an F in Evil if their master is a villain, and are in no way sad or angry their last boss is gone. If their current boss were to meet an untimely end (or just get fired/demoted) they will happily offer their services to their replacement, even if they just saw how the new boss killed the old one! Despite their desire to be close to the reins of power, they never harbor any ambitions of their own boss-hood, much less betraying their current boss, at least until the new one pushes them out of the job, anyway. They don't care who is in charge so long as they're the right-hand man.
Like the name says, the Professional Butt-Kisser is a career sycophant and Yes-Man.