1. For me, testosterone primarily feels like the ability to focus and critically think - like my head was foggy before and is now clear. Everything seems to be logical, and my ability to troubleshoot complex issues is dramatically stronger when my T levels are good. Without T, everything feels extremely emotional and even minor things feel like they're high-stakes. That's not to say that I don't feel emotion with T, rather the emotions are more appropriate for the situation. I do find that I care less about people in general when on T - For example, when I see a stranger with a problem I don't feel like I have an obligation to help them whereas before I had an intristic need to help everyone around me.
2. I had many biological changes, such as a change in body fat and muscle, significant facial/body hair, hair thinning - which is a miserable conversion in and of itself, period loss, and changes in my genitals that I would prefer not to discuss. All of these were euphoric to me, meaning they made me feel good and more like myself.
3. I think that the best way for a man to understand a woman and vice-versa is to roleplay online as the opposite gender. For example, you may have noticed that people are more willing to help and harass you as a female character. Male characters mostly get ignored.
4. I thought on this one for a while and couldn't come up with a strong response that doesn't just parrot the talking points of this community.
5. I felt indifferent and uninterested in strip clubs before transitioning. I still feel the same way. They just seem like a bad time to me.
6. Before transitioning I didn't understand gender dynamics at all. I thought it was a level playing field and had no grasp on the many courtesies and dangers that women face that men do not, and vice-versa. It's often frustrating to see people rag on men's or women's behavior/privilege/issues, because people rarely hit the mark on reality.

I did also want to mention that one thing blew my mind - The way that the dynamics of a room change when it's all men, versus when there's a single woman in the room. With all men, it seems like guys relax and suddenly don't feel the need to walk on eggshells. Social courtesies become significantly less important and men tend to communicate more directly. Next time you're in a room of all men and a woman walks in, keep an eye out for the subtle differences in how men behave.