The problem is trivial stuff like converting back and forth from degrees-minutes-seconds and decimal degrees. This is what I came up with to convert...
=INT(B3)+INT(MID(B3,4,2))/60+INT(MID(B3,6,2))/3600
That's ridiculous for a common function. I guess I could turn it into a macro, but I seem to remember a couple other problems where something simple ended up being a minor ordeal. I haven't fooled with it in over a year though. One other reason I wanted it was to have something on my phone as an emergency backup, but I found an old program I wrote for the HP48, and I have that running in an emulator on my phone, so the basics are covered.
I used to work with a guy that was big into spreadsheets, and he tried to get me into it cause he knew I programmed calculators, but I'd look at it and think "I don't have time for this shit", and didn't pay it much mind. I wish I'd paid more attention. I don't work with spreadsheets much, but sometimes it would be really handy to manipulate numbers and fields.