Republican lawmakers left Washington this week in an upbeat mood after passing a major tax cut bill, and with a growing confidence that they can govern after an up-and-down year that still left them with a list of significant accomplishments.

The GOP misfired on repealing Obamacare, but was still able to eliminate the individual mandate penalty, and can still boast about Neil Gorsuch's Supreme Court confirmation and a rollback of several Obama-era regulations. They're ready to be judged on that record.

"It started off slow. It took us a while to get something done," said Rep. Steve Stivers, R-Ohio, the chairman of the National Republican Congressional Committee. "It entered like a lamb and ended like a lion, so I feel good about that."

With the tax package passed and ready for the president's desk, Republicans are also relieved to have gotten a big-ticket item done in 2017. Sen. Thom Tillis, R-N.C., argued it would have been a "huge letdown" if the tax efforts had finished just as the healthcare repeal did.

However, they are more than willing to note the roller-coaster nature of the year that forced members to get used to a new normal, which included waking up to 6 a.m. tweets from the president about a myriad of issues, some of which they deemed to be a detriment to their work on Capitol Hill.

"Topsy-turvy. It's ending on a high note," said Rep. Mark Sanford, R-S.C., when asked how to characterize the year on Capitol Hill. "I think much of the year has entailed a lot of noise that has maximum inflamed and outraged people. At minimum, it's confused them."

"I think the Trump tweets have been counterproductive. I think that they have hurt from a messaging standpoint," Sanford continued. "We'll see if the tax bill makes up for that and more."

Republicans are also showing signs that they're getting used to Trump doing his thing on Twitter.

Rep. Peter King, R-N.Y., an ally of the president's, spoke about one instance in February in the aftermath of Trump's address to a joint session of Congress where he was universally given high marks, even among Democrats who despise him. However, the boost from the speech was short-lived.

"And then two days later he says Obama was wiretapping him from the Oval Office," King lamented. "That sort of knocked out all memory of the [joint session]."

"But that's him," said King of his ability to stay on message. "At this stage of his life, he's not going to change. I ask people close to him. They say 'c'mon, we tried. Forget it, it's not going to happen.'"

Despite the messaging issues, Republican lawmakers give Trump high marks for his first year performance, thanks in large part to finally getting tax reform done.

"With tax reform, I move [the grade] to a B+," said Stivers. When asked what the pre-tax reform grade was, the Ohio Republican declined to say exactly.

"It was below that," Stivers said.