Both my wife and I have had problems trying to start the Mercedes in "D" but in our defense, it was our first auto-on-the-floor car. All previous cars were either column-shift auto or floor-shift-manual. We did learn, eventually.

I was driving to Chicago. We probably had stopped five times between gas, food, bathroom, etc. I like to take breaks and move around, so it is normal. Had put in about 700 miles, and stopped outside of Chicago (Gary) to get gas. Turned off the car, all was well. Turned it on and got nothing. Just the gauges fluttering (electronic gauges not in an MB) a bit and a soft click upfront. Great. So what do I know? Nothing. Figure something broke (stressful). Tow truck comes and tries to jump it, car won't jump. Even more stress. If the battery was just dead, it would have jumped, right? Finally we try shorting the starter with the tow truck on jumper leads, thinking that maybe the starter was shot... Car fired right up. Turns out it was a shorted cell in the battery. A multimeter would have let me know that the battery was only at 7.9V and thus it was bad, rather than anything else.

In the past two years I had batteries fail suddenly, without warning, in both my non MB vehicles. Also (as expected) the 8 year-old battery in a seldom used 240D.

A short story -
Many years ago, I got a late-night call from my friend Linda from the parking lot of her employer.
Conversation went something like this -

Linda "My Geo won't start. I had to borrow a co-worker's cell phone. Do you think maybe you could come out here and take a look at it?"

Me "What's the car doing?"

Linda "Nothing happens when I turn the key"

Me "Do the lights work?"

Linda "The lights? Yes the headlights work fine"

Me "what about the warning lights on the dash? Do they come on when you turn the key?"

Linda "Yes"

Me "What gear is it in?"

Linda "What GEAR is it in?"

Several seconds pass, then the sound of a car starting.

Linda "Never MIND!"

Happy Motoring, Mark