The understanding is that gambling/betting on outcomes of events/things is considered haraam because it has potential for losses, or gains from something they didn’t really ‘work for’, compulsive behaviour and/or mental stress. Is that right (and exhaustive) from an Islamic perspective?
What about situations such as a game, of say basketball, where one’s a participant in a ‘loser treats to lunch’ game or shooting some pool where the ‘loser pays’? What’s the situation here, as this is something the player could win by playing well; but at the same time there is an equal chance of loss?
I’d appreciate any input. 
Thanks.