As I got older I no longer had tantrums, but had outbursts instead.
When I was a younger adult I had the most disruptive angry outbursts that involved screaming, shouting, swearing, yelling abuse, and excessive crying, all caused by an adrenaline rush that just caused me to fly up in a rage. While it was lucid and I knew and understood what I was doing, I still couldn't contain myself. But, no matter how angry I was, I never, ever hurt anybody. I never even damaged objects, except for my poor bedroom door that I kicked so much my foot went through.
I never even thought about physically harming anybody. Shouting and screaming abuse was the worst I did, which I know isn't right either and I do regret it. Luckily my family were very forgiving and they knew I didn't mean any of the bad things I said, but it was still upsetting for them at the time. I felt like a demented lunatic during those outbursts. I was just driven by this anger. I was like a bomb that could go off at any time. I was advised to count to 10 when feeling angry, but then when the anger came on it was too intense to stay calm and count to 10.
The triggers to these stupid outbursts were fear, depression or panic.
I had a weird phobia of snow, which would often set me off into one, irrationally thinking that by yelling and swearing the snow might all melt away. Or I was hoping for my mum to give me a solution or reassurance, but she was quite matter-of-fact when it came to my stresses and anxieties (even though she suffered with anxiety and stress herself).
Depression was the worst trigger of an outburst. Often when I was reminded of how lonely I was by seeing my cousins getting on in life while I wasn't, I would get resentful and angry and beat myself up about it - physically. I remember one time I was on the kitchen floor screaming "I WANNA BE NORMAL? WHY AIN'T I NORMAL LIKE EVERYONE ELSE IN THIS FAMILY?" It was actually very disturbing for my family to witness, as they were afraid I was descending into madness. It took me about an hour or two to calm down, and I then cried because I felt very bad for behaving like that, and apologised to my family.
Panic used to set me off too, sometimes. I remember when there were nuclear bomb threats around 10-12 years ago, and I asked my mum if it was just scaremongering news. But she said it wasn't scaremongering, it was real. When she was extremely anxious she'd be quite matter-of-fact about it, when what I really needed was reassurance and comfort. So I went into one, throwing myself on to the floor and screaming "NO!! NO!!! OH GOD!!!!!" I was hoping that by getting into a massive panic I might be reassured and comforted, but it didn't work. My brother then came in and shouted, "shut up! There ain't gonna be a nuclear bomb!" That was all I needed, and I calmed down and tried to rationalise instead.
There's probably many threads on Wrong Planet about it, all created by me lol.