Maybe I would say that such people are those who misunderstand what gambling really is, especially what is called "winning opportunities" in gambling, so they tend to focus too much on the idea or idea of earning by always trying various ways just to get a win. They do not understand that all wins in gambling are nothing more than "possibilities" which means that it does not mean that it will always happen or does not mean that it is easy to get.
As you said that they will be very worried when betting even though the amount of the bet is not too large, it is because they are too focused on winning or the intention and purpose of gambling to get a win or earn so that defeat is a result that is really difficult for them to accept because it is not what they want. Therefore it is always advisable to understand what gambling activities really are, it's not just about winning but there are possible risks that will always occur at any time and defeat can never be separated in gambling, because after all gambling is an activity that risks your money for two possibilities at the end of the session, namely between winning or losing, with you having this understanding then I think it will not be difficult for you to become a responsible gambler by being able to accept the fact of losing at the end of the session.
Too much focus on winning in gambling really destroys the psychological comfort and pleasant mood of the player quite strongly. Therefore, of course, when starting a game, it is probably best not to think about winning at all, but to think that the game is a great way to spend your time and this is a test of your mental abilities, your luck, fortune and just the whole complex of your thoughts about yourself. And by the way, about the world around you, including the world of the game. It seems to me that this is the optimal approach to the game in general always, and especially of course when you have free time and decide to play.
Exactly, there are many things that are always suggested to people when they are involved in gambling, not only suggesting to limit the amount of money and time that is bet but also the expectation of winning should also be one of them, because as you said that this mindset can threaten mental and psychological comfort, and I would also say that the impact of focusing too much on winning or having too high expectations of winning can really increase the possibility of disappointment when in the end the results are not as expected.
This is what makes a gambler dominated by emotions when they experience defeat and this is also what leads a gambler to a much worse situation such as losing a larger amount of money through scenarios of various aggressive actions because emotions dominate.
So the conclusion is to know and understand what activity you are facing, because that way you should not be too excessive in placing expectations on winning.