We have all met a person at some point in our lives who believes they know it all. This person is usually so deluded in their all encompassing knowledge that they are beyond help and advice.
Don't be this person. The cup must always be half empty.
I myself, ashamedly, have been guilty of believing I knew everything I needed to know about Muay Thai. That was about 5 years ago and the amount I know now compared to how little I knew then just goes to show the level of ignorance I had in believing I knew it all. I will never make that mistake again. I will always be a student no matter what titles i win, what ranking I achieve, who I train or anything else. The minute you think you know it all, you're in trouble because there is only one place to go if you're not moving forward and that's backwards.
Complacency is death.
Nothing stays the same, change is constant and guaranteed so it's up to you to make sure you are constantly evolving.
There are only so many moves in Muay Thai, punches, teeps, elbows, knees, kicks and clinch. But the possible combinations and options of when, where and how to use these moves within a fight are infinite. Not to mention even if you train everyday for the rest of your life you will most likely not perfect any single one of these moves or, if you do manage to perfect one, be competent enough to pull off that same perfect technique every time under the pressure of a fight.
So stay a student. Take every opportunity to learn something new or a new way of doing something you already do. Watch other people everyday and take what you like from them. Listen to people who offer you advice and tactics, and practice things you aren't comfortable with even if you don't quite understand them yet (as long as they came from a reliable source).
And be grateful for every lesson you've learned, especially those which you learned in the ring because they are the hardest lessons of all and also the most important.