Smash-hit comedy The Big Bang Theory had its final curtain call last night, just 72 hours ahead of the final episode of Game of Thrones.

Fans of the hugely popular sitcom gave an emotional farewell to Sheldon and friends after the last episode aired in Canada with an hour-long finale after 12 years and 279 episodes.

Now the end of one of the biggest shows in TV history is in sight: Game of Thrones will wrap up after eight seasons on Sunday.

Bill Brioux, TV critic and columnist at Brioux.TV, believes that what makes a TV finale great is when the show offers viewers a reward and ties up loose ends.

“I think the best thing a TV show can do is reward the viewers who watched it all those years, to give them something that they’ll just love and cherish,” Brioux told CTVNews.ca from his home in Brampton, Ont.

“To make them feel good for investing all that time watching the show. You don’t want to watch that finale and feel ‘I just wasted six years of my life watching Lost.’”

The very last episode of a TV show can be a make-or-break moment. Here’s Brioux picks for his best and worst endings.

Best:

1. Newhart - CBS - 1990

"In that episode, you see Newhart turning on the lights, he's in bed with his first TV wife, Suzanne Pleshette," Brioux said of the ‘80s hit starring Bob Newhart.

“He tells her he's had this crazy dream. He was with this other woman, Mary Frann.

"So, basically, they're suggesting the whole second season was a dream. A very, very funny episode."

2. Breaking Bad - AMC - 2013

"They gave you everything you'd hoped for," Brioux said of the critics’ favourite.

"They didn't leave loose ends. They explained things."

3. Six Feet Under - HBO - 2005

"At the very end of it, they showed all the characters -- how they ended their lives, as they grew old, when they died. And they did it all in the last five minutes,” Brioux explained of the drama, set in a funeral parlour.

“It was a very clever way to sum-up the whole story."

4. The Sopranos - HBO - 2007

"We're watching Tony in the booth with his family. Meadow's trying to park her car," he said of the show starring the late James Gandolfini.

"All of a sudden, fade to black. So, give them a blank canvas to make up their own ending. David Chase (writer and producer) was brilliant."

5. Mad Men - AMC - 2015

"We see that basically, the main character has crafted another brilliant advertising segment," Brioux said referring to Don Draper, played by Jon Hamm.

"And that's how they ended the show."

Worst: 

1. Seinfeld - NBC - 1998

"All the people they had wronged came back to the episode and they ended up in jail," Brioux said.

"That's a funny line, but it's not two hours of your life. It got stale and old, wasn’t very good."

2. M*A*S*H - CBS - 1983

"I hated the finale of M*A*S*H. It was 2 1/2 hours I'll never get back," Brioux said of the comedy.

"It seemed like five hours. It was longer than the Seinfeld one."

3. Lost - ABC - 2010

"It really was the one that said: ‘We're sorry you watched our show, we wasted your time, but we don't care,’" Brioux said.

“Nowadays you binge a show, back then you had to wait every week to see that thing and that’s a bit unforgivable.”

4. How I Met Your Mother - CBS - 2014

"People who watch the show were horrified, you killed our friend,” Brioux said of the sitcom.

“Terrible way to end a show."

5. St. Elsewhere - NBC - 1988

"The suggestion is, is that the entire series was all in the head of this child, what?," Brioux said of the hospital-set show.