Which one wins?
I had 77 in my hand.
He had J8 in his hand.
Community Cards on table:
8 8 7 2 2
So who wins here?
In a full house, 888xx beats 777xx. That is, the higher set beats the lower without concern for what the pair is. The cards in the pair are only important if both players have the same set, such as player A's pocket being 8 2 and player B's pocket being 8 7. This would give player A 88822, and B 88877.
A full house consists of a 'three of a kind' and a 'two of a kind' (='pair'). The one with the highest 'three of a kind' would have the highest full house. An example: Consider you have A2 and the other player has KQ. The board is: AA2KK. That would make a full house for you: AAA22 and your enemy as well: KKKAA. Still your full house is better and will win.
On your example you got unlucky since your enemy needed the remaining 8 or a J or any pair on the board. The latter happened.
hero 77 villain J8
Let's break it down
At this point you are only losing to
88 and 87
88 most people would play from any position - some would raise and some would call
A single 8 would typically only call from like A8 suited, suited connector, or one gap suited
J8 is not a likely holding unless you let them in cheap
But 77 is not that strong so you often want to get in cheap yourself
As Daniel said the over-pair is not a good thing for you as yes you made a boat but you are exposed to bigger boat to an 8 and any other pair including the board
A boat would protect you from a straight or flush but right now there is only 2 to the straight and you mention nothing about a flush draw
You can only improve with the case 7
At this point you are likely ahead.
If you have position I would just call a big bet.
Otherwise raise/bet 1/2 the pot to see where you are.
An 8 will call but unfortunately 88 and 87 would also call.
Even if you bet the pot you would probably not chase off an 8 and you don't necessarily want to chase off an 8 - you just don't want it to catch a boat.
You risk chasing off a blank that may have tried to bluff later.
And you risk chasing off a straight draw.
So not raising is also an option - or just put out a value bet. Your dream is for them to hit a straight and stack them so if you both have big stacks then slow play is maybe OK but a straight is going to see a boat on the table so you are not going to stack a good player.
No way that changed anything unless villain was on 82 and that is not likely
Unless villain has shown strength then raise / bet 1/2 the pot
Make them pay for 888
With the 8, 2 and the J they have 7 outs - they are not getting pot odds to call
This is where you need to SLOW down
If villain is still in the hand they likely have an 8 and you are dead
You are in check mode and if villain bets more than 1/2 the pot you need to consider folding
Yes they sucked out on you - that is poker
All you can do is not give them proper math to suck out