Thats probably not true, but bad beats can be more expensive in cash games, especially if you overplay your hand, because you play with a deeper stack on average. If I had to pick one typical mistake, beginners make in cash games, it would be to overvalue top pair in a single raised pot. If you have top pair and get raised on the turn or river, you should often strongly consider folding in a low stakes cash game. Example:
You raise


from HJ, BTN and BB both call. Flop comes



. You bet, BTN call, BB fold. Turn is

. You bet again, and now BTN raise. If you call here and then also call a river jam, more often than not you will get shown a hand like


,


,


or


and lose your entire stack.