I think it just depends. I've done a few TV shows...here is what the hosts were like.
Bobs Full House (Bob Monkhouse). Came and chatted with the 8 of us (recorded 2 shows at a time) and ran through the jokes he'd like to do, to make sure none of us were offended. Must have spent over an hour with us. A really nice bloke.
Telly Addicts (Noel Edmonds). He saw us in the waiting area when he arrived and introduced himself, 5 min chat then didn't see him until the show and not afterwards.
15-1 (WGS) As Cloverjo's hubby, he turned up, did the show, *** off.
Crystal Maze (Richard O'Brien) What a guy! Had dinner with the 6 of us at the hotel pre recording. The show takes 2 days to film and there is quite a wait between set ups, so many opportunities to chat. The first night it was one of the cameramens birthdays, so a bit of a party in the hotel bar...and I didn't pay! To be honest we didn't expect to win, but a brilliant experience.
Test the Nation (Anne Robinson & Phil Schofield). 180 of us in the studio, together with 8 'celebrities'. Didn't meet any of them except for a short interview with me by Phil and having my photo took with Anne and Phil as I was the studio winner.
Pointless (as said).
As I say, Bob Monkhouse and Richard O'Brien were really nice blokes.