Maths is a Hard degree, especially at Cambridge. That's a pretty negative spin.
I did Natural Sciences. I'd got top marks (100% or close to) in every single one of my 5 A levels (all the sciences, double maths). I got there, and no matter how much work I did, I couldn't get myself to a point where I was going to do well at the physics exams. I worked 80 hours a week, did or attempted properly all the questions we were set, attended every lecture, every supervision (bar one, where I was crying too hard to see never mind perform), did every past paper for the last 20 years and still got a third (in that part of first year). The rest of my marks were such I got a high 2:2 in first year.
Maths in first year (nat sci maths not mathmo maths) was taught by people who loved researching maths, not who loved teaching it. The teaching was often (to me) opaque, and I was someone who taught myself pretty much the whole of KS3 and 4 maths from the textbook.
I switched rapidly away from mathematically based subjects (having arrived planning to be a physicist), and had stressful but manageable 2nd and 3rd years.
Don't get me wrong, I still worked 55? hours a week, at least, in those years, and it was still mad busy and really really hard, and the stress made me ill, but I did also have a great time while all the above applied.
I learnt loads, I rowed, got involved with loads of college stuff, had great friends. The amount a crammed into my brain astonishes me. I have something to look back on that was so hard it still to this day reassures me that no matter what I will prevail (and I've done some pretty hard stuff since then).
I still genuinely don't know, looking back and knowing what I know now, if I would go back and do it again.