1. Heavily favorite team dey disappoint big time. Eg Argentina losing this week, Japan beating Germany. You bet and your ticket cut, no one saw Japan beating Germany and Saudi Arabia beating Argentina
2. Referee factor, player tempers and so forth e.g Zidane Headbutt, Maradonna hand of god
3. Home team advantage except Qatar. Most host often play very well especially if the Host nation is a football country, so if you bet against them , you might be dissappointed e.g Korea went far, Germany went far, even South Africa played well .
4. The use of VAR experience- some oblivious goal can be disqualified by a thread or a length of a footballer foot.
5. Unforseeable events. E.g Ronaldo was not well in France 98 Final.

In Summary - do not bet and save your money, the world cup is too unpredictable