When your mindset about gambling is just for entertainment, you can’t really expect to win.. just my observation. Because when I’m not serious about it, like when I treat it lightly especially in sports betting, I don’t study the games before placing bets. I usually end up losing more. I don’t lose big, but if you look at the record, it’s not profitable or even close to break-even.
But when I start believing that I can actually be profitable, that’s when I do the work. I study the games before betting, and that’s when I start getting better results.
Seeing gambling as an entertainment does not equal losing bets, part of the entertainment in gambling is winning too. It's just that they consider winning as a bonus, not a priority. Also, people who see gambling as entertainment do not take it as seriously as much as a gambler who only gambles to make a profit, but they can be serious enough that they still want to win.
In fact, when you make winning a priority, you're fooling yourself and entering a dangerous zone. You may think otherwise, but when it comes to gambling and betting, IMHO, expecting it to be a source of income is making a mistake since the first minute.
Nobody likes to lose, but one should be aware that chances of losing are higher than winning, no matter how good your strategy or analysis is. If you play games where skills play a role to some degree, having no clue of what you're doing and simply playing for fun will lead to a loss almost for sure, but even if you're skilled you will depend to a large extent on luck.
So yes, entertainment mindset can lead to more losses, but it doesn't mean it's bad, or worse than a winning mindset, when it comes to gambling.