As a seasoned Medic, all I have to say is:

EVERY FUCKING TIME.

A day in my life.

Sucks so much, though.

Gotta know who to hook up with.

Played way too much to not know this.

And I still haven't played after the "LOL IT'S FREE NOW SO HELLO BAZILLION NOOBS EVERYWHERE" update. It must be way worse now.

Make me glad I'm either engineer when I want to defend, or a scout when I want to... bonk... I do see this alot though but once in a while I see 3 or 4 Medics on 1 Heavy and every time I just have to stop what I'm doing and stare.

And this, ladies and gentlemen, is why I simply ditch those who pull a Leroy Jenkins. Players respawn, ubercharge doesn't. (Doesn't help that me + full charge = Sticky/Crit magnet)

That's one of the toughest parts of being a good Medic: Knowing when to follow your man right into Hell's teeth because this is your -chancce- to do something -awesome-... and when it's time to pull back and prevent your foolish, foolish patient from getting you and your Uber killed, too.

It's pretty simple, IMO. If it's raining hell and you're under 97% charge, you shouldn't follow. You won't survive long enough to reach 100%. Anywhere between 97% and 100% is iffy, as a single sticky trap, crit or backstab can ruin the party before you get to release the uber.

I've also had the opposite problem with players. I uber them in the thick of fighting, and they just sit behind cover. Do they not realize they are invulnerable?

I've had the interesting problem of being a Heavy and running out of minigun ammo right before a Medic comes out of nowhere and ubers me.

Happens to me constantly whenever I am the medic teaming with a newbie.

Every
fucking
time.

Then don't follow them out there. Chances are, someone else will come along, and respawns take less time than it does to build up the uber gauge. That's my philosophy anyway. Also, often there's someone else who needs medicing. The duty of a medic is never over.