When the price increases, there are many who buy in the hype. That makes the mempool clog up and therefore the transaction fees increase since most of them want quick confirmations. What happens is quite natural then however: as long as people consider the fees are too high, they stop transacting and fees decrease. If you feel like .10c is too low and you afford to pay .12c, you will help with the increase of fees.

It's just a natural order in a decentralized world, although I would argue that the rich have a huge advantage over us since they will always afford to pay larger amounts for transactions.