I can't think of a more inane, grating filler expression than when a guy mumbles, "good times" for no apparent reason. It's awkward and meaningless, much like our conversation. *rimshot noise* And, they usually just don't say the phrase once; they repeat it a minimum of two times for extra effect. Guys who say it usually are known to buy gag gifts, wear shorts well into November, and heckle people from the away team at baseball games; they're horrible!
What can I say? I have an irrational hatred for this phrase. Are you wearing a what would Dave Coulier do (WWDCD?) bracelet because I'm pretty sure he would say "good times" during a lull in his stand-up routine between his Popeye and Bullwinkle impressions. I don't want to date Dave Coulier and I don't want to hear you say this phrase to me. Ever.
The only exception to this rule is when Jerri Blank from "Strangers with Candy" says it because everything she utters is hysterical. But, I feel like she is really making fun of people who say "good times," so it's almost avant garde. For the rest of humanity who choose to say it, I only have two words: BAD TIMES.