Hi Omar, thanks for your excellent question. I'm glad that you are interested in trading as someone who studies economics. It's true that buyers usually want prices to move higher, while sellers usually want prices to go lower, both of them stand to benefit if the price moves in their chosen direction.
However, it goes against human nature to sell at the highs and buy at the lows mainly because the highs are usually characterized by intense greed and the lows are usually driven by intense fear. However, if you can control your emotions and actually sell at the highs and wait to buy at the lows, then you have mastered the hardest bit of trading/investing.
Bonus tip: Did you know that technical analysis works largely because human emotions are very predictable and they have not changed for thousands of years.
You can learn more about trading/investing on other sections of this site and don't hesitate to ask more questions, I'll gladly answer them.