If you've ever attempted to write a book in the first person then you know that it's difficult to accomplish. It's difficult to do it without ending overusing the word 'I' or ending up with pages and pages of internal dialogue. These are traps that are difficult not to fall into. If all your character is doing is talking to themselves inside their head and there's no outward action taking place it quickly becomes boring. 

Here's an example -

I didn't want to go to work but I knew I had to. I grabbed my keys and went out to the car. I got in and started it and I drove to work.

Let's rewrite that and get out of the 'I' trap -

No one ever wants to work, do they? I know that I don't but if there's one thing I understand, no work means no paycheck. A look at the clock told me that it was well past the time I should have left. Of course, I was moving in slow motion. It was the norm most mornings for me.

"Keys, keys." My muttering overlaid the sound of things hitting the floor as they were tossed around during my key search. "Here keys, where are you? Ah-ha, found you!" Also the norm, never leaving my keys where they could easily be found. I left them in the microwave one time, I'm still not certain how. All right, now out to the car and off to work!

The second example has more descriptions and fewer sentences with 'I' in them. You learn a bit more about the character.  If you keep to internal dialogue the entire time readers will learn very little about your character. Their personalities won't come through clearly. The readers need to see them interacting with others. If everything takes place inside their heads you don't learn much that isn't colored by their observations. 

Take a moment and think about the saddest book you've ever read. What made it sad? It wasn't simply because something tragic took place in the book, it was because you got to know the characters while reading the book. You became invested in their lives and their story. Now, think about whether it would have been the same if you never read the book and instead heard it from a  friend. It wouldn't have the same impact. You wouldn't be as invested in the characters' lives hearing about them secondhand. It's the same when you're writing. Readers don't want secondhand information, they want to see things happening firsthand. If it's all taking place inside your main character's head they miss out. It's also very boring.

Instead of a character simply bemoaning the fact she was dumped, show us the scene. Let us see how she was dumped. Let the readers feel her emotions. 

Internal dialogue-

It was horrible. I sat there staring at him as he told me it was over. He told me he found someone else. Then he asked for the ring back. I was devastated that night and still haven't recovered.

External dialogue-

David smiled as he took my coat and pulled out my chair. "Let me help you with that."

It was our fourth anniversary and I was incredibly excited about this dinner. A little less than two months ago he'd asked me to marry him and that made this anniversary extra special. He'd gone through all the trouble of planning this dinner, it was very romantic of him. We had begun planning our wedding immediately, everything was so perfect. The restaurant was lavish and I knew it was nearly impossible to get a reservation because they booked up quickly.

"Thank you," I said as I took my seat. We spent several minutes looking at the menu and then placed our orders. I reached across the table and place a hand atop his. "Happy anniversary, darling," I told him with a smile.

He slipped his hand from beneath mine and looked away. "I already had this reservation so I figured we should at least use it but ..." He paused, swallowed, and then finally looked across the table at me. "Sharon, I'm sorry but there's someone else. I didn't know how to tell you but this has been difficult for me." 

"Difficult for you?" I squealed.

He hushed me when other diners began staring at us. "I'm sorry, it's not like I planned for this to happen! Kay and I reconnected last month through social media and it sort of ... happened." He shrugged.

"So you've been seeing this woman for a month? You let me continue to plan our wedding, you answered questions about venues, and you let me go on and on about wedding cakes!" I knew I was being loud and I didn't care.  It was either scream at him or allow the hurt he'd caused in and then begin weeping like a broken woman. 

"I'm sorr—"

"Stop saying that! You're not sorry or it never would have happened!" The statement left my lips on a wail.

"I know there's nothing I can say to make either of us feel any better."

"No, David, there isn't. You should have been man enough to tell me from the start instead of allowing me to get excited about this night! It's our anniversary and you're dumping me in the middle of a restaurant! Oh, but you're so very sorry so it's all okay. Screw you!" I threw my napkin down and rose.

He stood and reached for my wrist to hold me back but it wasn't the reason I believed. It wasn't because he wanted to take it all back and try to repair things between us. No, he wanted to take more from me. "Sharon, I uh ... I need the ring back."

"You what?" I yelled.

"Kick him in the balls!" a woman three tables to our right yelled.

"It's my grandmother's ring. Please, Sharon?"

"Bastard," I snarled as I wrenched the ring free and threw it at him. "Enjoy it, asshole!" I turned and stormed from the restaurant. It was a crappy parting shot but it was all I had. The valet guy got me a taxi. I maintained my composure long enough to give the driver my address before I burst into tears. 

The second one is longer for sure but it gives you a better look at what took place. You can feel her hurt and you see her interaction with David. You get to know the characters and understand them more. It's almost always better to write things out than to have a character say it happened. 

If you're writing in the first person then do this, go to a page in the book and look at the first paragraph on the page. Does it begin with the letter I? Now, look straight down the left margin, how many of the paragraphs begin with the letter I? If a lot of them jumped out at you then it's time for some rewriting.

The above image is the first seven paragraphs of the first chapter of a book  I read here on Wattpad and six of the paragraphs begin with 'I'. I only took a screenshot of the left edge because it's not my book and I don't want to mention who the author is. If you're using 'I' this much then it's time to reevaluate things. 

There is nothing wrong with writing in the first person as long as you keep from falling into the traps I've mentioned. I've read good and bad first-person narratives. It's all in the practice, in finding what works to keep you on track.