One of my favorite 'loser talk' phrases is 'I did the best I could', or 'thats all you can do' or 'you tried your hardest' or some variant of the above. Truth is..there is always room for extra effort and nobody really ever does the best they could, that implies there is no room for improvement.
Sid Savara Totally agree. As you mentioned, there are other loser talk excuses along the same lines, including the much more common - "Well, at least I tried". Whenever I hear myself say that, I ask myself "Really Sid? Did you just try? Not even tried your hardest, or tried hard? Just tried?"