Retrospect(ive) vs. Hindsight?

I use both words, but only now does it occur to me, what's the actual.difference?

Specifically this kind of usage:

• "in restrospect" (or "retrospectively") "we should have thought of that"
  
  vs
  
  "in hindsight we should have thought of that"

Retrospect refers to any instance of looking back at the past. Hindsight usually implies a realisation that you would have done something different, or seen a situation in another light, if you had known what you know today.

The main difference is connotation.

• Retrospect (first used in 17th century according to the OED) comes from the Latin retro- (back) and -spectus (from the verb specio, specere - to look or watch).

• Hindsight (first used in 19th century according to the OED) comes from Old English / Germanic hind (back, behind) and sight (see, look).

In terms of connotation, words with Latin origins in English tend to be heard as more technical or professional, whereas words from Old English or Germanic origins tend to be heard as more colloquial or to-the-point. (See this EL&U exchange, "Assessing Formality via the Root of the Word," for more pairs or triads of words that work similarly).

So these words preceded by "in" mean similar things and are often used interchangeably, but retrospect carries a whiff of the erudite while hindsight sounds a touch more brisk. That said, the connotations are pretty weak. For example:

In retrospect, it was the beginning of the end of Morris's tenure as head coach.

In hindsight, Perez regrets choosing McLaren over Ferrari