Indian behaviour i've noticed.
1) As soon as the tyres of the planes hit the ground, they get up grab their bags and head to the door. Despite pleas to remain seated they take no notice. The irony being most of the low cost carriers just turf you onto a bus to the terminal, so you gained no advantage.
2) The vast majority of these men are sex tourists, if you go by their behaviour in Pattaya and Phuket. Yes some come as families and they are the types of tourists Thailand should try and encourage, not these groups of single men. The indian tourists you get in Europe and America are the upper class.
3) For many it's their first international holiday, and bring some bad habits with them - like trash on the floor, the dreaded urinating on walls. My worst experience was when a mother told her child to just urinate in the pool (i can speak some hindi). A man nearby bought up some phlegm and just spat in the pool too. Another was passing by and decided to wash his sweaty face in the pool.
4) Thai's do not like Indians, and look down on them. They are very racist towards them if you can speak some Thai.
5) Whilst not as bad as chinese tourists around a buffet they come close for panicking the food will run out.
6) If a tour included food option, they will constantly complain about when food is coming. They will make sure they eat enough for 3 days.
7) They do not shop in any fancy malls. You go to any major mall, one thing you will notice how rare it is you see an indian.
8 ) They hit 7/11 and just completely ransack the instant noodle of the shelves.