I look at the list of diseases and think "which of those diseases do I want my child to get?"
Meningitis?
Pneumonia?
Polio?
Mumps which can cause infertility?
Measles which can cause deafness?
Hep B which is worse in children than adults?
Do I want my child to be miserable and potentially scarred by chickenpox?
No, I don't want any of those for my child. So I got them vaccinated.
Every time your child eats dirt, licks something that fell on the floor, or shares their food with the family dog, their immune system is meeting a MUCH greater diversity of possible nasties than any of the vaccines provide. Attending nursery or going to a soft play is as immunologically 'challenging' as a multi-disease vaccine, and most parents would do that without thinking twice.