Uber and Lyft drivers reveal the hardest parts of their jobs (UBER, LYFT)

On the surface, driving for Uber and Lyft is relatively simple: just pick someone up and take them to their destination.

But for full-time drivers on the ride-hailing platforms, there's plenty more work that goes into making sure they keep a top-notch rating — and that they can entice as many tips as possible.

We asked drivers for the most difficult part of their job. Despite the flexibility that working for Uber and Lyft can offer, many said sitting for long hours can get uncomfortable, as well as a lack of coworkers to socialize with. On top of that, the most lucrative times to drive aren't always the most convenient.

Here's what they said (last names have been removed for privacy):