Bear market makes it!

In bull market, Ethereum price rises and even only Ethereum price, it will do affect intensity of transactions on Ethereum network that will affect transaction fees. Worse, Ethereum is a backbone for many altcoin projects that build their platforms, networks, dapps on ERC20 chain. In bull market, people are greed and easily to bet with games, gambling, investment etc. that together make intensity of transaction becomes much higher than usual.

Consequently transaction fee rises dramatically in bull market and falls a lot to almost normal level in bear market.