> A not so obvious result that follows from making successive negative expected value bets, is that in the long run you are guaranteed to lose all your money (or ruin). Intuitively this makes sense as with each bet, you are losing money on average.

Expected value doesn't tell you much about the outcome of successive bets. Someone else can probably explain this better since it comes up on HN a lot (something about ergodicity and the difference between ensemble average and time average).

Quick example is if play a game of double or nothing on coin flips. This is a "fair game" because you pay x and get back 2x * 0.5 + 0 * 0.5 = x. But if you play more than one game you will very quickly get a "nothing" and can't continue.