I hate disappointing Sir and even when He'll say I did really well with.....whatever, I still feel like a failure. The times I mess up and know I did (which, thankfully are few and far between), I punish myself more than He ever would. However, it isn't realistic to please everyone all the time.

Regarding subs intentionally misbehaving; as the previous post mentioned, that could be their personality; they might not be aware of how they're being perceived. It doesn't necessarily negate how submissive they are. Or, they could be a bit of a brat and their Dom doesn't mind. This could also be a way of testing a Dom (though that's not something I recommend as it smacks of game playing). They may be very new or haven't yet figured out their place. It can be easy to admit to being submissive; being submissive in a D/s relationship is something entirely different.

That's the great thing about these relationships; before a collar is placed or any sort of commitment is made, if you take things slowly, you pretty much know before hand if you'll be a good match.