有点 vs 一点
yǒu diǎn vs yì diǎn
Comparing "youdian" and "yidian"
有点 comes before the adjective and complains; 一点 comes after it and asks for a change.
有点 + Adj. (complaint) · Adj. + 一点 (request)
How it works
这衣服有点贵，便宜一点吧 — this is a bit expensive, make it a bit cheaper. Both mean "a bit", but they sit on opposite sides of the adjective and do opposite jobs.
有点 describes an existing state you're not happy with. 一点 asks for or states an adjustment.
That's why 有点 rejects positive adjectives, while 一点 accepts anything: 大一点, 快一点.
Examples
zhè yī fu yǒu diǎn guì
这衣服有点贵。
This top is a bit expensive.
pián yi yì diǎn ba
便宜一点吧。
Make it a bit cheaper.
jīn tiān yǒu diǎn lěng, nǐ duō chuān yì diǎn
今天有点冷，你多穿一点。
It's a bit cold today — wear a bit more.