There is a big difference IMO between avoiding anger and suppressing it, especially for a long time. If one can avoid anger, great; no need to get artificially angry (if one knows he will likely be on hold for 45 minutes, he can call during a less busy time or pick a service that supports callbacks).

Suppressing anger for a while (by self-distraction, leading yourself to see the other side of the coin, whatever) might be worse than stepping out for 30 seconds and letting go (e.g., by laying waste to a plastic cup). My 2c.