Has there ever been a generation of Christians that didn't think that Jesus was just about to return?

I don't think so. Seems like there's been at least one apocalyptic prediction per generation for the past 2000 years.

There has never been a generation in which some small minority of Christians didn't believe that.

Plenty, but there will always be a few in each generation who don't know the scripture. The generation is defined by the few.

Peace be with you.

Not in the past 2000 years.

No. Starting with the authors of the gospels:

I tell you the truth, some who are standing here will not taste death before they see the Son of Man coming in his kingdom.” -Matthew 16:28

And he said to them, “I tell you the truth, some who are standing here will not taste death before they see the kingdom of God come with power.” -Mark 9:1

I tell you the truth, some who are standing here will not taste death before they see the kingdom of God.” -Luke 9:27

I don't think so. Jesus has been 'coming back' for thousands of years.

This keeps us trying to always be ready for Him and doing His will and work while we have something good to look forward to. Makes us happier than unbelievers. Also keeps us from 'drifting' away from our 'dock'.

No, it's just another means of indoctrination.

LOL sux 4 u because Jesus is coming back soon and is gonna roast ur salty ***

No.