that time when you pass a cv of your friend who is as qualified as you were good 2 yrs ago to your boss and next thing you know he is being offered a much better position than you have

That's normal - chances are if you were a "new" candidate you'd be in the same boat. Staying at one place for too long means you'll likely stagnate in terms of responsibility & pay, unless you really keep pushing for an increase year on year (and even then you're less likely to get it, as the budget for "giving existing people more" tends to be a lot less than the budget to "bring new people in.")

That's the main reason most people tend to move on to somewhere else after a few years.

@AlmondSauce This.

Be happy for the success of your friends, but be sure he returns the favor later!