Ever run into one of those people who pretends to be your friend but then slips up and reveals that they totally despise you?

What problem had Christie solved?

What has he done to "make this country better?"

During Christie's tenure, New Jersey's credit rating was downgraded nine times
(across Standard & Poor, Fitch Ratings, and Moody's Investors Service),
leaving only Illinois with a lower rating among U.S. states.

In March 2010, Christie signed into law three state pension reform bills, which had
passed with bipartisan support. The laws decreased pension benefits for future hires
and required public employees to contribute 1.5 percent of their salaries toward their
health care. The laws prompted a lawsuit by the police and firefighters' unions.[96] In
his campaign for governor, Christie opposed any change in pension benefits for
firefighters and law enforcement officers, including "current officers, future officers or
retirees". He described the pension agreement as "a sacred trust".

Maybe the "boo's" aren't personal, but a commentary on the failed policies and practices of his time as governor?  Look at it more as a "report card" than an insult.

Wow.  His reprehensible remark is equal to or worse than the remark that HRC said about her basket of deplorables.

So since he made that remark I'm gonna take a cheap shot at him about his girth. 

I used to look like that.

Not anymore.  Chris, you are a pathetic fatso.

Christi and Trump are quite similar. They were buddies but then they butted heads and now they try to act superior by insulting each other.