system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 what "bubbles" are (in regards to economics)

I've always had a hard time understanding what "bubbles" are. I hear people discuss housing bubbles, stock market bubbles, economic bubbles, etc. but I've never grasped a strong or definite understanding of what they are. 

Can someone please help me understand? Thank you I appreciate your time!
gpt
A bubble occurs when people artificially place value on something.  

For example, people thought that they could make money by buying a house, fixing it up, and selling it.  People were also willing to spend a little more on their purchase, thinking that their improvements would increase the value of the house whenever they sold it.  Some people did make money on this, as did banks.  Banks make money off of the loans people use to buy houses, so they were more than happy to give out loans to almost anyone who wanted one.  

However, as more and more people bought houses, something dawned on them: no one wanted to buy their fixed up house.  Not only could they not sell at their fixed up house at the new higher price, but the value of houses dropped so far that they couldn't even sell them at the price they bought it.  This loss of value is the "popping" of the bubble.  

This de-valuation effected those who weren't even out to make money.  An elderly couple who bought their house way back when for $130,000 may have been expecting to sell their house for roughly that much (and retire on that), but found it was now only worth $80,000.

This happened in housing and Tech Companies in the 90's.  Possible future bubbles include Facebook Stocks and College Education (if you spend $70,000 on a degree only to have no job to pay for it, then that degree isn't really worth $70,000).