Some emails Don't Download To Mail Client But Are On Web and Other Devices

Mail is behaving a bit strange this morning (and maybe has in the past).

I checked my emails on my tablet and phone earlier then back at my desk I noticed no activity since 5:00 am -- yet I'd read at least a dozen messages since that time. Eventually a few messaged came through but some I know I'd read just never showed up on my computer.

The messages are on my phone, on my tablet, on the web, ... but not in my Mail. And yes I've checked the junk and trash.

I closed and launched Mail. I shut down the computer and rebooted then again relaunched all with no luck.

My son told me he finds Mac Mail so buggy that he gave up and only deals with emails on the web but I sorta like using a computer based client.

My email is gmail and it is set up as an IMAP.

I'm running Mail Version 7.3 (1878.6) and OSX 10.9.5

Any ideas?