Looking back:
Brutaly blunt types, as if every 'unnecessary' kind word is costing them dearly to express. (The no fun types.)
Discounters. (The battling cheap types).
Those never sure how many they will show up with. (The mysterious types.)
Those that ask about every little detail as if everything is of paramount importance. (Exhausting types.)
Anyone that uses legal terms like 'contract', etc. (The 'lawyer' types.)
Comparers - to past places they have stayed in the past - "X place is the way a place 'should' be run". (Really?)
Lastly (applicable only to my type of place) - "What happens if a tsunami comes?" In the Carribbean? (The overly fearful type, or have no basic understanding of geography.) 😉
Seriously, it is a feel one develops over the time; it is very much a personal thing. I still will usually accept the above types, but on guard and have an idea how to approach them. Those that are open, sound friendly, are enthusiastic with some degree of humor are my favorites and I know upfront I can relax with.