"Hitler loved was vengeance" and of course this was his flaw - vengeance should play no role in military strategy. One of the first things one learns in Martial Arts training is that one must not allow emotions to intrude in combat. Of course many leaders and generals have allowed their emotions to blind them, and often this is why they failed. This is why the concept of Professionalism was so important. In war Rommel was a professional, Hitler was not. One does not go to West Point to learn vengeance.

Agreed, but didn't Churchill order RAF to attack Berlin after London was bombed?

And Dresden was flattened in response to Coventry.

And I believe that Hitler ordered the Blitz against London not simply because he was losing too many planes in the battle against RAF airfields, but because the RAF bombed Berlin. Hitler was certainly a tit for tat kind of guy, at least in the air war. When Lubeck was bombed he ordered the Luftwaffe to likewise attack English cities of historic importance. Hitler was very tentative in his attacks against Britain, unlike his bomb first-ask questions later approach to many other European cities. The British, on the other hand, went all out against Germany and German cities from the beginning.

Yes, Churchill did - but no one accused him of being a military genius. I think the only purpose for an attack that appears to be pure vengeance is to lure your enemy into a tit for tat game. Let me explain: You know the online game Red Orchestra? Remember the map with the frozen river and the two bridges? At least twice when my forces were trying to take the big bridge they were being held up by enemy arty. I would take the bunker across the river from the enemy spotter calling in the arty. Instead of hitting his forces at their end of the bridge, I would call in arty on the enemy spotter's bunker. Now my arty could not kill him because he was in the bunker - and what he should have done was keep calling in arty on my team. But what happened both games I tried this in was that the spotters would break off hitting my team and call in a tit for tat attack on my bunker. They'd do this EVEN AFTER I switched my arty to their forces trying to hold the bridge. So a seeming vengeance attack can play an Asymmetrical role. Of course it can also - in the case of Churchill play a propaganda role - likely the best know was the Do-very-little (Doolittle) raid done by the USA. But Hitler's use of V-2s as propaganda would have been better spent building aircraft and fighters.