I wish the 7 shuffle thing would stop getting repeated everywhere. It’s based off a faulty model, particularly for sleeved cards, since if we consider the deck as two piles left (L) and right (R), Pr[L|R] (the probability of taking from the left pile given the last draw was from the right), should be about 0.5 but is nearly 1 in many cases.
The riffle shuffle also has to be one of the only things you actually get worse at the more you practice it.
The riffle shuffle also has to be one of the only things you actually get worse at the more you practice it.