It seems at least when I play that if you get double suited cards, most of the time the flop will show the other 2 suits.
That’s the “perversity of Nature” at work. Also that because we’re paying close attention to the suits (because we want them to be favorable to us), we notice when they’re not what we hoped for. It’s an illusion, in other words. Keep track for a few thousand hands and you’ll see there’s no visible pattern.
A very similar discussion is occurring in the “The Fairness Debate”
There’s rather a lot to read there but you will find that nearly every question that you can think of has been addressed and, quite likely, some questions that you haven’t yet thought to ask
You’ve also removed 2 of the 13 cards of that suit from the deck when you have 2 yourself, leaving more cards of each of the other suits available to hit the board. You can look up the likelihood for hitting a flush draw on the flop, or a made flush, and then just track how often it happens to you over a few thousand hands were you see the flop with suited hole cards. I’m reasonably confident the values will converge pretty close to the predicted numbers over a sample of that size.