What does Genesis 31:27 mean?

Laban is confronting Jacob about secretly running away with his wives and children without saying a word. Jacob was inspired to leave, abruptly, thanks to Laban's cheating and scheming. First, Jacob was tricked into marrying both of Laban's daughters, and working unpaid for fourteen years (Genesis 29:20–28). Then, Laban accepted a payment system that he thought would greatly benefit himself, at Jacob's expense (Genesis 30:31–36). As it turns out, this deal was superintended by God (Genesis 31:10–12), who used it to greatly benefit Jacob, rather than Laban (Genesis 30:37–43). Seeing Laban's anger at a backfiring scheme, Jacob and his wives agreed that it was time to leave for Canaan (Genesis 31:3). After ten days, Laban and his men have discovered what happened, and caught up to the fleeing family.

Now Laban suggests that if Jacob had only told him ahead of time, Laban would have thrown a huge and happy goodbye party with music and laughter and celebration. This is almost certainly false; even if Laban convinced himself that he would have responded in such a way, Jacob would have known better. This comes across as the kind of manipulation Laban was known for. His prior actions certainly don't support a view of Laban as loving and supportive. Rather, he could be expected to be manipulative and greedy (Genesis 31:14–16).