You should have gone.
(If you had gone last year, the situation would be better NOW.)
You should have gone.
(The above assumes that the "better" part was in the past: You didn't go last year, and LAST YEAR it would have better if you HAD gone.)
If you saw my sister, you'd certainly know she was pregnant.
If we were warriors, we wouldn't have done that.
but we're not, and we did
If I were Clan Leader . . .
but I'm not
If you had helped me, I wouldn't be going to Washington next week.
but you didn't, and I am
If you had given me that kind of food, I would be strong today.
(but you didn't, and I'm not)
If I were hunting right now . . .
but I'm not
If you had loved me, I would have been so happy.
(but you didn't, and I wasn't)
If you loved me, I would be so happy.
(but you don't, and I'm not)
If it rained tomorrow, they'd do a dance.
(but it won't, and they won't)
If it were raining, (then) I couldn't go.