I think this same principle applies to pornography and casual sex. These are things we are naturally and strongly drawn to. They are desirable, but the effects are not lasting. In both cases there are no emotional attachments being made (at least not healthy ones). There is no relationship to continue the euphoria afterward, and so after the experience participants are left with nothing (except possibly an STD or a new baby in the case of casual sex, or the realization you just wasted several hours of your life in the case of porn). Often people express this as a strength of casual sex. People say all they want is sex with no attachments. But I feel like this is training oneself to avoid what would ultimately be a happier relationship.
In a traditional relationship, a strong emotional bond would (ideally) be formed BEFORE sex takes place. This means that after sex a couple would still be left with strong feelings for each other, as well as a commitment to each other because, hey, sex IS great and we can keep doing that. But now you are trained to maintain the more difficult parts of a relationship such as building trust, selflessness, and spending time together. This is more work, of course, and from the outside I can see why people might say 'Hey-I just want the sex.' But a strong relationship allows you to be happy with someone after the sex is over. Sex doesn't become the highlight of your day-it is an enhancer to happiness that already exists. This depends, of course, on the idea that you have a positive relationship already, which I know isn't always the case. But IDEALLY you have carefully considered who your partner is and developed positive personal traits that foster a happy relationship BEFORE you worried about sex to make sure you are emotionally compatible. (Too often I see people pursue a relationship with the focused idea of having sex, rather than how much they will enjoy spending time with the other person. This is a stupid strategy as sex will likely be a small part of your day).
Anyway same sort of problem with porn. Rather than training yourself to go out, meet people and build relationships, you train yourself to look for the quick and easy solution to satisfy your hormones. This means you are essentially robbing yourself of the satisfaction of building a positive intimate relationship with someone which can ultimately lead you to much greater satisfaction and happiness than an evening alone on the internet.