I've been on T for 1 1/2 months. The biggest emotional/mental change I've had is social anxiety- it's dropped significantly. For about 6 years, practically every time I went out into public I felt like like I was going to die, if I was in a group of more than 2 other people I'd be sweating and shaking, incredibly self conscious, and the self consciousness would trigger dysphoric attacks. Transition itself helped some, testosterone further eased outright panic. Especially when it comes to speaking, because my voice has dropped into a reasonable range now. Other anxiety related things, like OCD compulsions, are lesser and easier to manage.
I don't hate myself now. I feel like, good or bad, this is my body. It's working in synch with me. Having this significant of a change gave me the incentive to stop self-harm and claim my body as my own.
Physically: lower voice, more muscle tone, dick growth, thicker and oilier skin, more body hair (particularly on my thighs and stomach), signs of facial hair getting ready to appear, changes to my jawline and cheeks making me appear more masculine. I'd say my passing has changed from 50% to at least 70%.
On the negative/neutral side: Around New Year's I got some pretty bad hot flashes, and I continue to overheat more easily than before. I've been slightly more impulsive, and I'll get angrier faster. I can still control it fine, but it's there. Overall, I think my moods are more level, they just have a couple of obvious blips rather than being all over the place constantly. I've been sleeping more deeply, but my sleep schedule has also gone haywire- don't know if that's related or not. I'm much hungrier - I've gained 10 lbs - and the time that's not spent thinking of food is spent thinking about sex. Ah, puberty.