Honestly how quickly I forget about a loss depends on how invested I was in the outcome, which is probably the case for the majority of people. There's some losses in life I'll think about every now and then in a "life would have been quite different" way but they never dominate my thoughts so I think I'm doing quite alright.
I agree with you on this and it is not just all about the funds you must have put in the gambling but more in tune with the expectations you must have attached to it and how such big hopes, which mostly comes with bigger commitments financially, becomes futile when you lost your bet. I consider betting as a risky venture to go into and I will always encourage whoever wants to go into it to ask around and understand unfiltered information and experiences about gambling before making their final decisions as to whether to join or not.