Sen. Joe Manchin III (D-W.Va.) hates the Senate so much these days that he almost didn't run for reelection. That would have been a political crisis for Senate Democrats, who are defending nine other senate seats in pro-Trump states and don't have time to recruit a new candidate in West Virginia.

“This place sucks,” Manchin told Senate Democratic leaders before reluctantly agreeing to file for reelection days before the deadline, reports the New York Times's Jonathan Martin.

Americans don't necessarily disagree. But why, exactly, do longtime politicians such as Manchin openly trash the Senate? Some reasons are as old as the Senate itself, and some new in this hyperpartisan era.

Here are the top eight, some of which we outlined in 2015 when Sen. Marco Rubio (R-Fla.) said he was “frustrated” by the Senate.

1. No one knows who you are

A 2013 Gallup survey found that just 35 percent of Americans said they could name at least one of their representatives in Washington (although that's probably a generous number; Gallup pollsters didn't check to see whether people actually could.)

2. It's a thankless job

The most recent Gallup polling shows that 78 percent of Americans are dissatisfied with the job Congress is doing, numbers that are at or near the worst since Gallup began asking for Americans' opinions on the topic.

Americans are also skeptical of the power we give our lawmakers; an October 2015 Gallup poll found 60 percent of Americans are concerned that the federal government has too much power.

3. It's a thankless job especially for those who want to compromise

Congress has become significantly more polarized over the past decade or so. When it comes to elections, it's the poles of each party that have the most influence on who wins and loses. That means there's little to no incentive for either side to moderate to the center.

Jim Kessler, a former top Senate Democratic aide, describes the life of a senator in a competitive reelection this way: “You spend hundreds of hours locked in a room raising money, run for reelection and get blitzed by extreme attacks from the other side.”

4. When one party falters, so does the other

Manchin was expressing his frustration that Senate Democrats sided with the more liberal wings of his party when they tried to get a deal protecting “dreamers,” even if it led to a government shutdown. Moves like that alienate red-state Democrats like himself, Manchin told the Times.

But other students of the Senate say Manchin has it backward: It's Republicans who are making life more difficult for everyone in the Senate. The GOP is so ideologically wide that they've struggled to pass key legislation. And when Democrats are asked to help out, Republicans often can't get a majority of their party to cut a deal.

“Republicans have gone to the right much more than Democrats have moved to the left,” said Jim Manley, a former senior Senate Democratic aide.

5. Compromise isn't happening much, anyway

A bipartisan group of about 30 senators, including Manchin, found a way to end a government shutdown. But that was about the only compromise that's been happening in the Senate lately.

The Senate has come to have the worst of both chambers of Congress. It's deliberately slow, which was supposed to allow for high-minded debate and compromise. But the only real stuff that gets done is on a deadline, often behind closed doors by the majority party, without a single vote from the minority.

6. Everyone's too paranoid about losing their jobs to do real legislating

There was a time when Democrats controlled the House of Representatives for some 40 years, Kessler said, and swings in Senate control didn't happen nearly as often as they do today.

“Now, both leaders of both houses in the Congress, in the majority and the minority side, think they are one election cycle away from either gaining the majority or losing the majority,” Kessler said, “and it's influencing the behavior of how the bodies operate.”

7. There's less room for individuality

For much of the ’50s, ’60s, ’70s and ’80s, less than half of Senate members voted with their own party, according to the Vital Statistics on Congress analysis of partisanship. Voting along party lines has been rising steadily since then, to the point where in 2013, close to 70 percent of senators voted with their parties.

8. President Trump has exacerbated all of this

Compromise and moderation were difficult before there was a president lobbing insults at both sides via Twitter and using profanities to describe entire countries affected by immigration deals.

The issue has also been a great example of how Trump has been an unreliable negotiator. He has consistently moved the goal posts on what he wants out of a deal to protect dreamers, and as a result, there's a strong case to be made he's a big reason the government shut down.

On the other side, Trump is so controversial and unpopular that there is a faction of Democrats who are happy to give him a loss.

So the Senate has a lot going against it right now. And Trump is not a figure who inspires either side to put aside their differences and legislate.