I'm riding in the front of one right now. Maintenance is never proactive, refueling is something we do together, your only nemesis is from within - what am I referencing? (I know you thought I'd never ask).
Where to begin... having driven over, in, and off of the Darwinistic backroads of Cambodia, I clearly understand that just because one has 250cc's... doesn't gurantee that you won't have a giant (head on) bus passing a 4x4 truck passing a roto-tiller 'bus' passing various animals (generally cows as most other creatures move out of the way).
About that nemesis, it could just be the four dollars you saved on that second class bus ticket, the overnight ones without the toilet, or with my luck - getting the seat above it. Might just be nausea, not to worry a plastic bag will not drop out of the compartment above - though you'll wish it would... Let's not even get into how time passes on a bus
Forget about Rock, Paper, Scissors... it was 7a.m. and I saw 6" of AK-47 peaking out from under his fake leather jacket... Of course, he took a seat in the back with a nice vantage point. And people worry about bandits stopping a bus - take it in stride - if it was okay with Laos TSA (if they had a TSA) - it's okay with me.
In Laos & Thailand, buses seem to follow a certain bit of genuine etiquette, however, my heart is still with the Cambodian smiles and her people even if their concept of live and let live on the road is more 'Move or die' - there is no right and 'wrong'.