Both examples taken from ESPN about NFL gambling and losing on today's Vikings-Bills result.
I use to go to the horse races in Seattle when the track was called Longacres. Usually bet on a jockey named Gary Baze, won almost every bet.
On a road trip coming back from visiting family in NJ and PA I stopped in Reno and played craps at a 25c table - with 1 $10 roll of quarters I played for a couple of hours and walked away with my $10 roll of quarters. I had fun and lost nothing. I have never been to Las Vegas.
A friend of mine use to play blackjack - big money bets and ALL his winnings went to charity. He was a bit addicted to gambling and he justified his trips to Atlantic City by giving his winnings to charity. I saw he one time down $25,000, we ate dinner he went back to the table, recouped the $25,000 and left $3,000 ahead. He really like the adrenaline rush I guess and he really believed if he kept the winnings he would loose.
I don't bet on sports but when the Cubs went to the World Series I knew they would win the best of seven, I do wish I'd laid some money down - but then maybe if I bet I would have jinxed them.