Well,in childhood I was panically afraid from heights - anything above 2nd floor was uncomfortable,above 4th floor - pure fear. Of course I don't mean somewhere inside house,but was seariously afraid to go out on balcony of 4th floor when visiting a friend. I don't know why was that,weird thing - I could climb trees 20 meter high,no problems,but when I got out on roof of my house (5 floors and loft,so also ~20m),I could not get even near the edge,was scared completely. Now the fear is gone,not completely,I still feel uncomfortable in heights,but it's no panic fear anymore. No idea what has changed,maybe I'm older and wiser or just tired of life...
And spiders - I have no problem with them,I have held them in hand (not those big hairy ones though,just those 3-4cm found in latvian nature),watched them crawling,hanged them on their net and watched them climb up,I even took them and scared my ex,she was as afraid as you! I find them interesting. And they're good too - catching out those annoying flying insects!