A lot of bad beats are the result of something called “the schooling principal.” (“Schooling” in this case refers to fish, not education) To illustrate…
A player min raises to 2000 and gets 4 callers, making the pot 10,000.
Player 1 bets 5,000 on the flop, making the pot 15,000.
Player 2 is getting 3-1 pot odds and calls with a flush draw. This is a bad call at the moment, but the pot is now up to 20,000.
Player 3 is getting 4-1 and calls with an open ender. This is also a bad call for now, but there is now 25,000 in the pot.
Player 4 is getting 5-1 and calls with bottom pair, making the pot 30,000.
Player 5 is now getting 6-1 and calls with an Uno card and a fake Magic the Gathering foil rare because, hey, why not? The pot is now 35,000.
Because the fish have schooled, something magical has happened. EVERYBODY has risked 5,000 to win 30,000. EVERYBODY got 6-1 pot odds, and a lot of the bad calls have turned into good calls.
There is a good chance your blah blah blah is going to get beat when one of them hits a yadda yadda yadda.
How do you avoid this?
You don’t.
Yeah, there are things you can do to avoid letting this happen, at least to some extent, but the best defense is to understand the dynamics of the schooling principal and avoid the situation altogether when you can.
In my opinion, the schooling principal is the #1 reason this site sees so many bad beats.