How do you overcome the feeling after you lose?

How do you feel when you lose a chess game?  Are you ecstatic and happy ?  Or are you sad and lamented?

I feel sad because i did not teach my opponent a free chess lesson.  also i don't like it when i wasted all that time.  and sometimes on chess.com, my opponents insult me and laugh and call me stupid player

Your heart is racing, your breathing is shallow, and your mind can’t seem to focus on anything other than what’s stressing you out. Before you feel completely swallowed up by that overwhelming and panicky feeling, there are easy ways to get some quick relief.

Count your breath

This is one of the fastest ways to calm yourself. Sit down in as quiet a space as you can find and start counting your breaths. Every time you exhale, that’s “1.” When you reach “5,” start again from “1.” In demonstrating this simple but effective breathing technique, Dr. Andrew Weil suggests that you don’t try to influence your breath -- it may be fast and shallow when you start -- but simply focus on counting it. Breathing activates your parasympathetic system (the one responsible for relaxation) and helps your mind quiet down.

Go for a 10-minute walk outside

Walking activates nerve cells in your brain which help you relax, and being outside will give you a quick shift in perspective. Don’t worry about how fast you move; just go at whatever pace seems right (when you’re already stressed, you don’t want to push yourself more). But do try to keep your torso straight and walk as you would if you felt confident -- studies show that your posture affects the positive impact of your walk.

Schedule your stress

This might sound counter-intuitive but give it a shot: Allot yourself a set amount of time to think about what’s stressing you out. Actually schedule it on your calendar and say, “For the next 20 minutes I’m going to think about why I feel so overloaded.” Consider writing it down (studies have shown it actually helps reduce anxiety). At the end of your “stress time,” you’re done. While your brain won’t forget your stress, allowing it a set period of time to focus on it should make it easier to move on to something else.

Focus on something that’s good

In one study, 67% of people who consider themselves good at managing stress said they regularly focus on what’s positive or good in their lives. When you’re in the middle of a stress storm, focusing on something good (no matter how small) might seem like a ridiculous idea, but try it.

Practice some self-compassion (a.k.a., give yourself a break and go get a Whopper with Bacon and Cheese from Burger King, YUM!)

Studies show that when you’re kinder to yourself, you’re happier and less depressed, so when you’re overwhelmed by stress, do something nice for yourself. The way you would act toward a friend who told you they were stressed out is how you should treat yourself. Eat something you enjoy, make a little more free time in your schedule, take a yoga class that chills you out.

Write down something you’ve accomplished recently

A lot of our daily stress centers on impending tasks that are overwhelming. “You can do it!” pep talks seem silly when you feel overloaded, so instead, write down a few things you’ve recently done or accomplished. It’s a good way to feel more productive, and it will help make what’s coming up feel more manageable.

Didn't read the entire OP, but the above advice is what I try to follow.  I'm happy to lose online when I can learn something; isn't online really just training anyway?  The only down side to losing (online) that I can see is your rating drops so low that you get terrible opponents, but then, just think of all the wins you'll rack up : )

... also i don't like it when i wasted all that time.  ...