Interestingly one of my pet peeves with the original C&C as well as most RTS games is that they are way too easy for about 80% of the game and painfully hard for the remaining 20%, nothing like getting stuck halfway through a game because you just can't get past some ridiculously hard level (bonus points if it's one of those C&C trademark "fuck this strategy shit, let's just give the player two engineers and a commando" levels that are basically squad tactics and involve no large-scale strategy whatsoever).
I lost count of the number of times I had to replay those levels. They were some of the most aggravating and some of the best levels. It was kind of refreshing to have one of those every so often to break up the whole "let's get tiberium/gold/whatever, make a whole bunch of (insert favourite unit here) and go blow the crap of the enemy on a massive scale."
"I think trash is the most important manifestation of culture we have in my lifetime." - Johnny Legend