Sayyiduna Anas (may Allah be pleased with him) said that when the Messenger of Allah (peace and blessings be upon him) shook hands with someone, or a man shook hands with him (peace and blessings be upon him), he would not withdraw his hand until the man withdrew his own; when he turned his face toward someone, he would not turn his face away until the man turned his face away; and he (peace and blessings be upon him) would not sit in a gathering with his legs stretched out.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20790