"Minor things like your email client"
You obviously have never been forced to use Lotus Notes. I spend about 10 minutes every day waiting for that POS software just to update it's display. Another 20 minutes a week working out how to do something that is banal in any real email client. That's over an hour each week wasted on crappy software. One hour of my time, especially at the companys expense, is not minor.
When you spend all day working with software, and a lot of time with a particular app like an email client, the choice of software has a huge impact on your work environment.
Minor: no. Major.