If you have time to kill before your crossing, you can wander round Folkestone if you want. But that involves finding your way into town, and finding your way back again - easy enough with a Satnav, I suppose, but it's pretty rare that I could be bothered.
If you get there early and they aren't busy, you can usually take the next shuttle crossing, even if your booked crossing isn't for an hour. The software offers you the option when you check in. Scrap that for bank holidays, of course, and also if there's a breakdown. Then it's chaos, and they get quite strict about you travelling on your booked crossing. Fair enough, I suppose.
Which can mean you hanging about the terminal, generally kicking your heels. What is there to do?
There's a duty free shop, although as the duty on stuff in France is considerably less than in the UK, there seems little point to it. There's a money change bureau. WH Smith for all your books and magazines and sweets. Ladies, Gents and Disabled loo. Starbucks. A couple of fast food counters. And that's about it. Outside you can walk your dog in the special dog-walking area.
It isn't very exciting I'm afraid. Normally you aren't going to be here long, and quite often I go straight on past the terminal and into the queue for the train, even straight on to the train if I'm lucky with the timing.