A thing that might be true however is that you don't ask them what you were doing wrong. Perhaps your Samus was overtly obvious in what is was going to do next (like if I do an aerial on you, and you shield, I know like a lot of the time you'll upb out of shield, so I pillar to keep you on your toes). Self diagnosing yourself to why you can't beat Shane or Jesse is like self diagnosing yourself with cancer. It's just too complex to figure out yourself. A lack of skill compared to them may be obvious, but obviously your mindset wasn't working as well either.
So in other words, play the big players and get their feedback as to why they could beat you. It might not be your character that's lacking, it could be you, as irritating as that may sound. No I'm not saying you're bad, cause you're not, I'm just saying you might be using the wrong tricks in match or the wrong strategies at the wrong times. Some thing to know are that Samus has suuuuuper obvious recovery. Unless you sweetgrab the ledge, Falco for example will have a very fun time just doing dropzone jump dair at the right time.
....Also I eventually just adopted the attitude that no one likes to lose to a **** like me :3