Thank God for that, the Nazis may have won the war, had Hitler not had to bail out Mussolini's chestnuts in Greece and Yugoslavia, otherwise he would have launched Operation Barbarossa earlier, which may have allowed them to win the war before the harsh Russian winter set in in 1941.
The earliest Adolf could have jumped opn Barbarossa was about a week earlier than he did. Turns out the weather had a lot more to do with any delay than Yugoslavia, Greece and Crete. It was a VERY wet Spring, especially in Ukraine, and the Germans had to wait for the ground to dry out sufficiently for operations [remember, the German Army was about 80% to 90% horse drawn, and in 1941, most Grenadiers rode in trucks, not half-tracks.
Where pulling Mussolini’s chestnuts hurt the Germans was in wear and tear on the vehicles used in “25” and “Marita”, and the airborne losses [troops and Ju-52s] in “Mercury”.
As for the problems that arose later in ‘41 for the invasion, blame the split in the German command over how to proceed once Smolensk was taken [Hitler had to referee that one], and Halder and the General Staff’s almost overt refusal, in developing the plan for Barbarosa, to do what Hitler wanted.