To start, a major reason for this trend is peer pressure. Seeing everyone wearing the "hottest" clothes and using the newest phones makes you feel like you also have to follow or else you'd look weird and feel out of place. Moreover, you want to fit in, make friends and be as cool as others so you think following trends is the best way to do so, even if it's costly.

Additionally, it can also be because you simply find a certain trend interesting to you. When something is trendy it's usually because there's something unique and stimulating about it that it activates a part of your brain to think that you should do the same. For instance, if there was a trend in wearing comfortable, but not so fashionable, clothes to work, I would, personally be interested in following.

Over some time, we've had certain trends that isn't exactly considered safe or ethical, like the "devious lick" trend where students would straight up steal things from their schools. In contrast, however, we've also had environmentally beneficial trends, such as the "visco" trend where you do questionable things but in the end still protect the ocean. Efforts spent in both categories have had great impact on the world, so it is up to each individual to decide what should be trending and whether it's for a righteous cause or to create disorder and chaos.

In summary, the efforts spent in following trends is from both internal and external influence. It is the responsibility of everyone to follow and create the right trends and address the trends which are morally incorrect.