Please answer my following questions.
1. Sometimes I see some people using "all the time" and other people using "all the times"? Which one is correct?
2. When I tell people that I have "a couple of" things. People would think that I only have "2" things. But I actually mean "a few of" things. What does "a couple of" actually mean? Does it also mean "a few", "several"?
How about "I'm sorry for all the times I let you down"?
In general, though, use "all the time" unless you are specifically talking about certain moments (times).
I agree that "couple" literally means two, but it is not unusual for people to mean "a few" or "a handful" when they say "a couple." Like "I met a couple friends and we had a couple beers." It might have been 3 friends and 5 beers.