Is this grammatically correct and natural?

Q. If you use social media sites, what motivates you to post your comments, pictures, or videos?

A. There are three my motivations to post my comments, pictures, or videos on social media sites.
First, I post something about what is so funny, interesting, or wonderful that I would like to share with my friends or introduce to them. For instance, If I find a funny video made by a team of comedians, I share the video with some friends of mine who likes comedy.
Second, I post fabulous photo because I would like to boast of living fulfilling life and being happy. For instance, I would like to post a photo of a trendy café on Instagram.
Third, I post what I feel in my daily life and what I think about today’s world or our country. I can settle down if I write what I feel in my daily life on twitter. Also, I can share my thoughts about today’s world or our country with a lot of people living in various areas.

Question

Is this grammatically correct and natural?

Q.  If you use social media sites, what motivates you to post your comments, pictures, or videos?

A.  There are three my motivations to post my comments, pictures, or videos on social media sites. 
First, I post something about what is so funny, interesting, or wonderful that I would like to share with my friends or introduce to them. For instance, If I find a funny video made by a team of comedians, I share the video with some friends of mine who likes comedy. 
Second, I post fabulous photo because I would like to boast of living fulfilling life and being happy. For instance, I would like to post a photo of a trendy café on Instagram.
Third, I post what I feel in my daily life and what I think about today’s world or our country. I can settle down if I write what I feel in my daily life on twitter. Also, I can share my thoughts about today’s world or our country with a lot of people living in various areas.

Estarianne · Answer

I have three motivations to post comments, pictures, or videos on social media sites. 
First, I post things that are so funny, interesting, or wonderful that I would like to share them with my friends. For example, If I find a funny video made by a team of comedians, I share the video with some friends of mine who like comedy. 
Second, I post great photos because I want to show myself living a fulfilling life and being happy. For instance, I would post a photo of a trendy café on Instagram.
Third, I post what I feel about my daily life and what I think about today’s world or our country. I find it calming to write about my daily life on twitter. Also, I can share my thoughts about today’s world or our country with a lot of people living in various areas.

Hoid · Answer

Here's what I would change personally. They're in parentheses. I also removed some words and switched some things.

A. (I have) three motivations to post my comments, pictures, or videos on social media sites.
(Firstly), I post about what's funny, interesting, or wonderful that I would like to share with my friends. For instance, if I find a funny video made by a team of comedians, I share the video with some friends of mine who (like) comedy.
(Secondly), I post fabulous (photos) because I would like to (display) (a fulfilling and interesting life). For instance, I would post a photo of a trendy café on Instagram.
Lastly, I post (about thoughts I have) in my daily life; this includes what I think about (my) country (and the world today). It's calming to write what I'm feeling on Twitter. Also, (these thoughts can reach people living in various areas and may have some merit).

I switched the word "boast" with "display" because boast implies a tone of bragging or excessive pride. Not sure if that was the intention, but you can revert it back if it was.

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