Nothing wrong if you're winning. Losing on the other hand, now that is so wrong especially if the money you gambled with is a hard earned money. Better stay safe and don't gamble.
If you scare about gambling then gambling is not for those people because in these games you can lose more than making money. As long as one does all these things within a limit then nothing is wrong but if overdone then everything is wrong. Like how you spend some money on other entertainment purposes like if you fix some money for gambling and never exceed that limit then all are okay.