Ugh, Calculus, the derivative of all evils.
Okay okay I realise that what I just said above is stupid since Calculus is an important tool for technology and most of the items in our everyday lives, yadda yadda yadda. Also, you do have to use Calculus in Chemistry, I did a stage 1 Chem course once where calculus is used in something like kinetics and rates of reaction, didn't like it much though. Also, I have to do more calculus for my CompSci degree, so hooray for me I guess, NOT. Infact I think anyone can learn it if they put their mind to it, but if you're like me, and you think math is overall quite boring and gives you headache from time to time, it can be tough.