The only part I'm "scared" of is the CPU as its the most delicate part. I'm glad I've not had to change it in 5 years. One time removing the fan from an old Pentium 4 yanked the chip out with it and could have easily broken it. I've been wary ever since. I fear making an expensive mistake as I'm a bit of a clutz at times.
well thats likely from someone going a little crazy with the TIM.