There are a couple of things you need to do here.

First you need to reality check your observation. You need to analyze the all-in situation and determine if you were actually ahead when you thought you were. If you go all-in against someone with your two pair AFTER he's made his straight - it's not a bad beat - it's you putting in money when you are behind and losing.

Second, even if you are a favourite, you need to quantify how much of a favourite you are. When you go all-in are you a 70/30 favourite? an 80/20 favourite? Think about it. Think about it some more. What does this mean? If there is only one card in the deck that will save him and only one card to come, how often are you really winning? Maybe 98% of the time. How often are you losing? Maybe 2% of the time. You have be mentally and emotionally prepared to lose. Because it will happen. It may only happen 2% of the time but it WILL. If it never happened, then - and only then - would poker be rigged

Third, consider this: Now that you've looked at the situation, you've determined that you got your money in as an overwhelming favourite and you've lost - stop. Go back one step. You have managed to create a situation where you were a favourite to win lots of money. You don't just play one poker hand and then retire from poker. Your goal as a player is to consistently make good decisions and create situations where you are a favourite when the money goes in. You have done it in this case. This is good. You're allowed to feel good about it. Because, if you manage to do this consistently over hundreds and thousands of decisions that you do correct where you have secured yourself this edge you will win some, lose some and the amount of your wins will approximate the odds of winning in an individual case.

If you suffer a bad beat, stop. Think. You got your money in ahead. This was a good decision - given many more of those you win lots of money and the fact that you lost this one must not affect how you think or play. You must continue to get your money in well and you will profit.

If you give a bad beat, stop. Think. You got your money in behind. This was a bad decision - given many more of those you lose lots of money and the fact that you won this one must not affect how you think or play. You must stop getting your money in bad and you will profit.

You must judge the quality of your decisions without considering the outcome - because 2% chances do happen, and they happen often. And they are memorable. And at the same time - they are completely and utterly irrelevant.