Especially if you're unlucky enough to have Rogers as your service provider!!
Tell me about it. I actually dumped Rogers several years ago not because of poor coverage here, but in Newfoundland. I work as comms support for the Targa Newfoundland road rally (almost) every year (didn't get to go this year due to other commitments), and if you have a Rogers phone, you are in dark territory pretty much as soon as you cross the Outer Ring Road in St John's. There's one Rogers tower in a town called Clarenville, a few hundred km up the coast, but other than that, you may as well make smoke signals.
Bell Aliant has a cooperative deal with TELUS so that your phone works on their network there, and ever since I switched to TELUS, it's been hard to find a bad spot on the island.
Here, TELUS has very fine coverage where I am, although there are two bad spots - one in Redwood Meadows, where the closest towers are shielded by ridges and hills (though they're working on plans for a tower at our firehall, to rectify that), and another area that is poor is west of Bragg Creek, again, due to topography. Comms in Kananaskis are getting better; last year I had coverage in Station Flats, west of Allen Bill Pond, which I never used to get before. You can also get coverage in McLean almost all the way into the campground.