USB Port on Mac - Shockingly unreliable

I've been working with Arduino boards for a long time, but can never seem to get a reliable connection over the USB (especially on my Mac).
I'm at my wits end with this, and almost given up using Arduino boards because of it.
What is going on? Can anyone shed some light?

Never had a problem on PCs running Linux or Windows.

Don't know about overpriced Macs. Don't have the $ for them.

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Please provide more details about what you mean by "can never seem to get a reliable connection over the USB".