Problems With Fantasy Analogies
In Season 6 of Buffy the Vampire Slayer, it becomes clear that Buffy's friend Willow, a powerful witch, is using magic too much. It's clearly intended as an analogy for drug abuse, as she starts partying with a fellow witch and using magic all night long, and then going to a guy who does weird magical things to her that clearly create a 'high'. Finally, she ends up putting Buffy's sister Dawn in danger by accidentally summoning some sort of demon-thing that attacks them, and after that she declares to Buffy that she's going to stop doing magic - 'it's not worth it'.
Replace 'magic' with 'drugs', and that story works fine. Person uses drugs for fun, shirks responsibilities, then puts someone they care about in danger and decides that drugs aren't worth it. That's a story that often happens in real life. Now, that bit would have come across as poorly written with drugs, too, because of how much they sped the process up, but it wouldn't have been nearly as bad.
But Willow's magic was not equivalent to drug use. Willow's magic actually did things, very valuable things. Towards the end of Season 5, Willow saved all of their lives several times with her magic, such as when she projected a magical shield around a building they were hiding in so the knights attacking them couldn't come in. At the beginning of Season 6, she brought Buffy back from the dead, a spell which was for the most part the right thing to do (not so much for Buffy, who was in Heaven, but Buffy's absence put her town and her loved ones in serious danger). Drug use doesn't save lives (unless you're talking about prescription drugs, but that's different). Given that Willow has actually saved many lives with her magic, it doesn't make sense for her to just give up doing magic all together because she overdid it a few times. It would make sense if the only benefit of her magic was to make her feel good.
I'm sure there are many other examples of people force-fitting a fantasy situation into an analogy for real life, and getting something that doesn't make sense as a result. It seems to me that writers like that should really make a choice. Either:
a) Design a situation that really does parallel what they're trying to make an analogy for, such as if Willow's magic was limited to making illusions only she could see (which would necessitate giving up on using magical solutions for plot problems).
b) Explore the situation your characters are actually in rather than trying to stick to things that fit the analogy you're making. For example, if Willow realized that magic was addictive but also extremely useful given the problems their team faces, and worked on figuring out how to control her use of magic so that she could still save people's lives. Or, if she couldn't control it somehow, made a choice between losing control of herself and saving lives (I'd like to see a story like that sometime, it would be an interesting dilemma).