As mentioed there, what's your gearing? I used to have to get off on really steep hills when I had a standard double chainset with 23 at the back. I put a compact at the front and got up all but the very steepest (25% +) hills, and finally I caved in and put a 26 and 29 at the back and up I went! Don't need to get off at all now, but sometimes it feels like walking would be faster!!

Once you've done it, the mental block will be blitzed and you'll be happier and happier to attempt it again.