I don't think trying one's hardest is a set characteristic but varies with the task and circumstances. One can be tired, bored, anxious, uninterested or unmotivated to perform and that's fine, if that's what we want at that time with that task. I think when others tell us we're not trying our hardest it's because they've seen us in a similar situation trying harder and being more successful.

Other people say what they see and feel and are a great source of information about the world around us and how we appear "out there" or to those with whom we're currently interacting. We can't really say whether what they say is true or not, it's what they see and feel, not about us other than it might be their view of us. So, when someone says something about me I look to see how it might help me and use it/don't use that information, depending.

I was quicker finding my therapist last time because someone I trusted told me to "smile". It wasn't the first time an acquaintance had said that to me in a short period of time so I looked inside and realized I really was unhappy/needed some help, sooner rather than later.

I think if I'm trying hard or not trying hard, it shows. If I get a discrepancy between what I think and what others tell me from outside, then I tend to look and see if I can be smarter about my trying or better understand why they are seeing what they say they're seeing. Or, if it's a task I don't want to do or don't find important, I own up to that also.