I'll try to go question by question.

Can an ADHD person control their behavior sometimes?
Yes, but not always. It takes an incredible amount of effort sometimes for us to change our behavior and to self-regulate. This can be made easier by medication or other self-management strategies that we learn over time. Unfortunately like any disorder/condition (depression, diabetes) it cannot be shut off or made to disappear. ADHD people are often accused of faking because of the seeming inconsistency of some of the symptoms. That's the nature of the disorder, however. Symptoms vary in terms of severity and frequency.

Is it common for ADHD people to seem like they're not listening to you?
Yes. Very. It can be incredibly hard in a conversation to focus on a person talking to you. It's easy to get distracted by any number of things such as what's going on outside the window, a noise down the hallway, a feeling in your clothes, or even just thoughts in your head. It's incredibly easy to get distracted internally and it makes it hard for us ADHD folk to pay attention and retain information. It can be helpful when you're speaking with someone who you know has ADHD to ask them to try to focus in on you or ask them if they're able to have a conversation at that point in time. Some of us just need the right time and right space to be able to give you our undivided attention. It's hard for non-ADHD people to understand the amount of mental energy that goes into basic things like conversations or getting tasks done during the day. Sometimes we just don't have the resources to maintain that level of attention, and it can come across as flippant, rude, or dismissive.

Do ADHD people obsess over things like phones or social media?
Yes. ADHD is in part a dopamine disorder, from what we understand so far. It means that we often impulsively engage in or seek out behaviors or activities that give us an immediate reward. If we're doing something boring (i.e. cleaning or homework) and we are offered the opportunity to watch a video, dance to a song, respond to a text, or scroll Twitter, we will usually pick the thing that is most emotionally or mentally stimulating for us. This isn't to say that it's always okay. In a lot of ways this is a bad behavior that we have to learn to adjust. But it can be a challenge that takes time. Self-regulation isn't a forte for all of us. We have to find ways to mitigate distractions and avoid getting sucked into the impulsive digital high.

Do ADHD people refuse to get help or diagnoses?
Yes. ADHD is a disorder that is bound to shame. People are often called lazy, stupid, fakers, or flaky. We often get criticized for our struggles and we are reluctant to go to professionals who would do the same. Or worse, we could go to a professional and they could completely disregard our struggles and tell us it's something else or not real. It is incredibly painful to have a big part of your identity invalidated. Sometimes ADHD folks are reluctant to seek treatment because they don't like how medication makes them feel or they don't like the work that goes into therapy or coaching. This isn't that unsimilar from things like depression or Bipolar Disorder where people don't want to get treatment because they don't want to change how they feel. When you live with symptoms long enough you begin to internalize them as a part of who you are. If, for example, I'm used to being very creative and impulsively taking on new and exciting projects, it can be hard for me to adjust to not having that drive or not feeling that spark as easily. People usually have valid reasons for not wanting to seek care, sometimes based on past experiences from having done so. Other times we are uninformed and don't seek care based on misinformation or stigma.

Can ADHD people be overly emotional?
Yes. There's a new concept in the ADHD community being discussed which has been promoted by Dr. William Dodson, an ADHD expert and psychiatrist. He talks about Rejection Sensitive Dysphoria. I'd say it's worth reading about. In general, emotional dysregulation is common with ADHD. We can be very sensitive, especially when it comes to receiving criticism or feedback. We've often been told in our lives that we were behaving badly, not doing something right, or failing at living up to expectations. It's easy to have low self-esteem and to be reactive to any critique. That's not uncommon. It may be hard to understand when you're doing something like setting a simple boundary, but we need context and patience to help us understand what you mean. What you say to us is not always how we interpret it or feel about what was said.

Why don't people with ADHD tell you sooner?
I mentioned this above a little bit, but ADHD carries with it a lot of social shame. Even from your post I can see some of the common beliefs about ADHD. It's easy to discount the validity of what it is. A lot of people don't disclose their ADHD for fear of how it will effect relationships, jobs, or even their day-to-day safety. It's similar to why some people don't disclose if they have dyslexia, OCD, or an eating disorder. You don't always want people to know your business, and you don't know who is safe and how they'll respond if you open up.

Can people with ADHD improve without medication?
Yes. From the research, though, medication is effective for about 80% of people with ADHD. People who don't want or don't respond to medication can use other strategies and coping skills to mitigate some of the challenges of ADHD. ADHD coaching is growing in popularity and it is a great way to tackle things, as is Cognitive Behavioral Therapy. What's more common, though, is that we with ADHD learn certain coping skills to help us navigate life and live with the challenges we face. For example, I often struggle to keep track of items that are important like clothes for work, car keys, badge, etc. I make sure that each night I lay out everything I'll need in the morning and put it in all one place. You could say that because I am able to do that intentionally that maybe my ADHD isn't as bad as I say, but you don't see that this is a skill I've had to develop and practice over a course of decades. We all find ways to cope with our challenges. It's hard for others to see that, and also sometimes hard for us to explain. It can be useful to ask a person with ADHD, "What kinds of things do you do on your own to manage your symptoms?"

Does medication help with focus and behavior?
Yes, it can. It doesn't take away everything, especially behaviors. It can help with focus, but it's not like a brain pill that suddenly gives you superpowers. For me, my medication calms my brain a little and it lets me do things that are important like completing a task from start to finish, keeping track of projects that I leave open or unfinished, and generally feeling calmer and less restless in my chair or my body. It doesn't take away the other challenges I face, and when it wears off in the evening all of my symptoms come rushing back. Medication is not a panacea. Medication is a tool, and like any other mental health condition, it can make it easier to do the real work of managing the ADHD in our daily lives.

I hope some of that information helps!