What is the most cost-effective and refreshing way to take a train from Shenzhen to Changsha?

Cheapest: Shenzhen west green leather car, skylight and fan, as long as there are not too many people, it is quite enjoyable.

Cheapest and cheapest: hanging tickets.

The most cost-effective: Luohu to Wuhan T95 or T96, fast, affordable and comfortable.

The fastest and most expensive: high-speed rail.

The fastest, cheapest, freshest and most comfortable five-star enjoyment: get on the high-speed rail without a ticket, find an empty carriage to dismantle a stool to build a soft berth, find a drifting conductor to chew on it, and several windows next to it are smashed because of unhealthy air conditioning (be careful not to smash too much, the wind will be strong).