Comparing date field object with global variable "now" gives unexpected result
now represents the current DateTime so unless you specify exactly the correct time in your field the condition deliveryDate == now will never become true. If the user visits the page one second earlier or one second later the condition will fail.

For example: if your date is 2018-06-13 12:00:00 and now is 2018-06-13 12:00:01 both of your conditions will always fail. now|date_modify("+ 1 day") will result in 2018-06-14 12:00:01 and 12:00:00 is not 12:00:01

you'll need to equalize the time or format it differently

{% if deliveryDate.modify('midnight') == tomorrow.modify('midnight') %}


or 

{% if deliveryDate.format('Y.m.d') == tomorrow.format('Y.m.d') %}


You can read more about it in the docs